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hsum_of_finsupp {f : α →₀ (hahn_series Γ R)} : (of_finsupp f).hsum = f.sum (λ a, id)
begin ext g, simp only [hsum_coeff, coe_of_finsupp, finsupp.sum, ne.def], simp_rw [← coeff.add_monoid_hom_apply, id.def], rw [add_monoid_hom.map_sum, finsum_eq_sum_of_support_subset], intros x h, simp only [coeff.add_monoid_hom_apply, mem_coe, finsupp.mem_support_iff, ne.def], contrapose! h, simp [h] en...
lemma
hahn_series.summable_family.hsum_of_finsupp
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "finsupp.mem_support_iff", "hahn_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
emb_domain (s : summable_family Γ R α) (f : α ↪ β) : summable_family Γ R β
{ to_fun := λ b, if h : b ∈ set.range f then s (classical.some h) else 0, is_pwo_Union_support' := begin refine s.is_pwo_Union_support.mono (set.Union_subset (λ b g h, _)), by_cases hb : b ∈ set.range f, { rw dif_pos hb at h, exact set.mem_Union.2 ⟨classical.some hb, h⟩ }, { contrapose! h, ...
def
hahn_series.summable_family.emb_domain
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "not_not", "set.Union_subset", "set.range" ]
A summable family can be reindexed by an embedding without changing its sum.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
emb_domain_apply : s.emb_domain f b = if h : b ∈ set.range f then s (classical.some h) else 0
rfl
lemma
hahn_series.summable_family.emb_domain_apply
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "set.range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
emb_domain_image : s.emb_domain f (f a) = s a
begin rw [emb_domain_apply, dif_pos (set.mem_range_self a)], exact congr rfl (f.injective (classical.some_spec (set.mem_range_self a))) end
lemma
hahn_series.summable_family.emb_domain_image
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "set.mem_range_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
emb_domain_notin_range (h : b ∉ set.range f) : s.emb_domain f b = 0
by rw [emb_domain_apply, dif_neg h]
lemma
hahn_series.summable_family.emb_domain_notin_range
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "set.range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hsum_emb_domain : (s.emb_domain f).hsum = s.hsum
begin ext g, simp only [hsum_coeff, emb_domain_apply, apply_dite hahn_series.coeff, dite_apply, zero_coeff], exact finsum_emb_domain f (λ a, (s a).coeff g) end
lemma
hahn_series.summable_family.hsum_emb_domain
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "apply_dite", "dite_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
powers (x : hahn_series Γ R) (hx : 0 < add_val Γ R x) : summable_family Γ R ℕ
{ to_fun := λ n, x ^ n, is_pwo_Union_support' := is_pwo_Union_support_powers hx, finite_co_support' := λ g, begin have hpwo := (is_pwo_Union_support_powers hx), by_cases hg : g ∈ ⋃ n : ℕ, {g | (x ^ n).coeff g ≠ 0 }, swap, { exact set.finite_empty.subset (λ n hn, hg (set.mem_Union.2 ⟨n, hn⟩)) }, appl...
def
hahn_series.summable_family.powers
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "hahn_series", "powers", "set.finite_singleton", "set.mem_Union", "set.mem_singleton", "set.mem_union_left", "set.mem_union_right" ]
The powers of an element of positive valuation form a summable family.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_powers : ⇑(powers x hx) = pow x
rfl
lemma
hahn_series.summable_family.coe_powers
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "powers" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
emb_domain_succ_smul_powers : (x • powers x hx).emb_domain ⟨nat.succ, nat.succ_injective⟩ = powers x hx - of_finsupp (finsupp.single 0 1)
begin apply summable_family.ext (λ n, _), cases n, { rw [emb_domain_notin_range, sub_apply, coe_powers, pow_zero, coe_of_finsupp, finsupp.single_eq_same, sub_self], rw [set.mem_range, not_exists], exact nat.succ_ne_zero }, { refine eq.trans (emb_domain_image _ ⟨nat.succ, nat.succ_injective⟩) _, ...
lemma
hahn_series.summable_family.emb_domain_succ_smul_powers
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "finsupp.single", "finsupp.single_eq_of_ne", "finsupp.single_eq_same", "not_exists", "pow_succ", "pow_zero", "powers", "set.mem_range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
one_sub_self_mul_hsum_powers : (1 - x) * (powers x hx).hsum = 1
begin rw [← hsum_smul, sub_smul, one_smul, hsum_sub, ← hsum_emb_domain (x • powers x hx) ⟨nat.succ, nat.succ_injective⟩, emb_domain_succ_smul_powers], simp, end
lemma
hahn_series.summable_family.one_sub_self_mul_hsum_powers
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "one_smul", "powers", "sub_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_aux (x : hahn_series Γ R) {r : R} (hr : r * x.coeff x.order = 1) : 0 < add_val Γ R (1 - C r * (single (- x.order) 1) * x)
begin have h10 : (1 : R) ≠ 0 := one_ne_zero, have x0 : x ≠ 0 := ne_zero_of_coeff_ne_zero (right_ne_zero_of_mul_eq_one hr), refine lt_of_le_of_ne ((add_val Γ R).map_le_sub (ge_of_eq (add_val Γ R).map_one) _) _, { simp only [add_valuation.map_mul], rw [add_val_apply_of_ne x0, add_val_apply_of_ne (single_ne_ze...
lemma
hahn_series.unit_aux
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "add_valuation.map_mul", "con", "ge_of_eq", "hahn_series", "left_ne_zero_of_mul_eq_one", "map_one", "mul_assoc", "one_mul", "one_ne_zero", "right_ne_zero_of_mul_eq_one", "smul_eq_mul", "with_top.coe_add", "with_top.coe_eq_coe", "with_top.coe_ne_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_iff {x : hahn_series Γ R} : is_unit x ↔ is_unit (x.coeff x.order)
begin split, { rintro ⟨⟨u, i, ui, iu⟩, rfl⟩, refine is_unit_of_mul_eq_one (u.coeff u.order) (i.coeff i.order) ((mul_coeff_order_add_order u i).symm.trans _), rw [ui, one_coeff, if_pos], rw [← order_mul (left_ne_zero_of_mul_eq_one ui) (right_ne_zero_of_mul_eq_one ui), ui, order_one] }, { ri...
lemma
hahn_series.is_unit_iff
ring_theory
src/ring_theory/hahn_series.lean
[ "order.well_founded_set", "algebra.big_operators.finprod", "ring_theory.valuation.basic", "ring_theory.power_series.basic", "data.finsupp.pwo", "data.finset.mul_antidiagonal", "algebra.order.group.with_top" ]
[ "hahn_series", "is_unit", "is_unit_of_mul_eq_one", "is_unit_of_mul_is_unit_right", "left_ne_zero_of_mul_eq_one", "right_ne_zero_of_mul_eq_one", "units.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_local_ring_hom_of_le_jacobson_bot {R : Type*} [comm_ring R] (I : ideal R) (h : I ≤ ideal.jacobson ⊥) : is_local_ring_hom (ideal.quotient.mk I)
begin constructor, intros a h, have : is_unit (ideal.quotient.mk (ideal.jacobson ⊥) a), { rw [is_unit_iff_exists_inv] at *, obtain ⟨b, hb⟩ := h, obtain ⟨b, rfl⟩ := ideal.quotient.mk_surjective b, use ideal.quotient.mk _ b, rw [←(ideal.quotient.mk _).map_one, ←(ideal.quotient.mk _).map_mul, ideal...
lemma
is_local_ring_hom_of_le_jacobson_bot
ring_theory
src/ring_theory/henselian.lean
[ "data.polynomial.taylor", "ring_theory.ideal.local_ring", "linear_algebra.adic_completion" ]
[ "comm_ring", "ideal", "ideal.jacobson", "ideal.mem_jacobson_bot", "ideal.quotient.eq", "ideal.quotient.mk", "ideal.quotient.mk_surjective", "is_local_ring_hom", "is_unit", "is_unit_iff_exists_inv", "map_mul", "map_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
henselian_ring (R : Type*) [comm_ring R] (I : ideal R) : Prop
(jac : I ≤ ideal.jacobson ⊥) (is_henselian : ∀ (f : R[X]) (hf : f.monic) (a₀ : R) (h₁ : f.eval a₀ ∈ I) (h₂ : is_unit (ideal.quotient.mk I (f.derivative.eval a₀))), ∃ a : R, f.is_root a ∧ (a - a₀ ∈ I))
class
henselian_ring
ring_theory
src/ring_theory/henselian.lean
[ "data.polynomial.taylor", "ring_theory.ideal.local_ring", "linear_algebra.adic_completion" ]
[ "comm_ring", "ideal", "ideal.jacobson", "ideal.quotient.mk", "is_unit" ]
A ring `R` is *Henselian* at an ideal `I` if the following condition holds: for every polynomial `f` over `R`, with a *simple* root `a₀` over the quotient ring `R/I`, there exists a lift `a : R` of `a₀` that is a root of `f`. (Here, saying that a root `b` of a polynomial `g` is *simple* means that `g.derivative.eval b...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
henselian_local_ring (R : Type*) [comm_ring R] extends local_ring R : Prop
(is_henselian : ∀ (f : R[X]) (hf : f.monic) (a₀ : R) (h₁ : f.eval a₀ ∈ maximal_ideal R) (h₂ : is_unit (f.derivative.eval a₀)), ∃ a : R, f.is_root a ∧ (a - a₀ ∈ maximal_ideal R))
class
henselian_local_ring
ring_theory
src/ring_theory/henselian.lean
[ "data.polynomial.taylor", "ring_theory.ideal.local_ring", "linear_algebra.adic_completion" ]
[ "comm_ring", "is_unit", "local_ring" ]
A local ring `R` is *Henselian* if the following condition holds: for every polynomial `f` over `R`, with a *simple* root `a₀` over the residue field, there exists a lift `a : R` of `a₀` that is a root of `f`. (Recall that a root `b` of a polynomial `g` is *simple* if it is not a double root, so if `g.derivative.eval b...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
field.henselian (K : Type*) [field K] : henselian_local_ring K
{ is_henselian := λ f hf a₀ h₁ h₂, begin refine ⟨a₀, _, _⟩; rwa [(maximal_ideal K).eq_bot_of_prime, ideal.mem_bot] at *, rw sub_self, end }
instance
field.henselian
ring_theory
src/ring_theory/henselian.lean
[ "data.polynomial.taylor", "ring_theory.ideal.local_ring", "linear_algebra.adic_completion" ]
[ "field", "henselian_local_ring", "ideal.mem_bot" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
henselian_local_ring.tfae (R : Type u) [comm_ring R] [local_ring R] : tfae [ henselian_local_ring R, ∀ (f : R[X]) (hf : f.monic) (a₀ : residue_field R) (h₁ : aeval a₀ f = 0) (h₂ : aeval a₀ f.derivative ≠ 0), ∃ a : R, f.is_root a ∧ (residue R a = a₀), ∀ {K : Type u} [field K], by exactI ∀ (φ : R →+* K) (...
begin tfae_have _3_2 : 3 → 2, { intro H, exact H (residue R) ideal.quotient.mk_surjective, }, tfae_have _2_1 : 2 → 1, { intros H, constructor, intros f hf a₀ h₁ h₂, specialize H f hf (residue R a₀), have aux := flip mem_nonunits_iff.mp h₂, simp only [aeval_def, residue_field.algebra_map_eq, eval₂_at_a...
lemma
henselian_local_ring.tfae
ring_theory
src/ring_theory/henselian.lean
[ "data.polynomial.taylor", "ring_theory.ideal.local_ring", "linear_algebra.adic_completion" ]
[ "aux", "comm_ring", "field", "henselian_local_ring", "ideal.quotient.eq_zero_iff_mem", "ideal.quotient.mk_surjective", "local_ring", "local_ring.ker_eq_maximal_ideal", "local_ring.mem_maximal_ideal", "mem_nonunits_iff", "ring_hom.map_sub" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_adic_complete.henselian_ring (R : Type*) [comm_ring R] (I : ideal R) [is_adic_complete I R] : henselian_ring R I
{ jac := is_adic_complete.le_jacobson_bot _, is_henselian := begin intros f hf a₀ h₁ h₂, classical, let f' := f.derivative, -- we define a sequence `c n` by starting at `a₀` and then continually -- applying the function sending `b` to `b - f(b)/f'(b)` (Newton's method). -- Note that `f'.eval...
instance
is_adic_complete.henselian_ring
ring_theory
src/ring_theory/henselian.lean
[ "data.polynomial.taylor", "ring_theory.ideal.local_ring", "linear_algebra.adic_completion" ]
[ "aux", "comm_ring", "finset.mem_Ico", "finset.range_one", "henselian_ring", "ideal", "ideal.add_mem", "ideal.mul_mem_left", "ideal.mul_mem_right", "ideal.neg_mem_iff", "ideal.one_eq_top", "ideal.pow_le_pow", "ideal.pow_mem_pow", "ideal.quotient.mk", "ideal.smul_eq_mul", "ideal.zero_mem...
A ring `R` that is `I`-adically complete is Henselian at `I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integrally_closed (R : Type*) [comm_ring R] [is_domain R] : Prop
(algebra_map_eq_of_integral : ∀ {x : fraction_ring R}, is_integral R x → ∃ y, algebra_map R (fraction_ring R) y = x)
class
is_integrally_closed
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "algebra_map", "comm_ring", "fraction_ring", "is_domain", "is_integral" ]
`R` is integrally closed if all integral elements of `Frac(R)` are also elements of `R`. This definition uses `fraction_ring R` to denote `Frac(R)`. See `is_integrally_closed_iff` if you want to choose another field of fractions for `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integrally_closed_iff : is_integrally_closed R ↔ ∀ {x : K}, is_integral R x → ∃ y, algebra_map R K y = x
begin let e : K ≃ₐ[R] fraction_ring R := is_localization.alg_equiv R⁰_ _, split, { rintros ⟨cl⟩, refine λ x hx, _, obtain ⟨y, hy⟩ := cl ((is_integral_alg_equiv e).mpr hx), exact ⟨y, e.algebra_map_eq_apply.mp hy⟩ }, { rintros cl, refine ⟨λ x hx, _⟩, obtain ⟨y, hy⟩ := cl ((is_integral_alg_equi...
theorem
is_integrally_closed_iff
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "algebra_map", "fraction_ring", "is_integral", "is_integral_alg_equiv", "is_integrally_closed", "is_localization.alg_equiv" ]
`R` is integrally closed iff all integral elements of its fraction field `K` are also elements of `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integrally_closed_iff_is_integral_closure : is_integrally_closed R ↔ is_integral_closure R R K
(is_integrally_closed_iff K).trans $ begin let e : K ≃ₐ[R] fraction_ring R := is_localization.alg_equiv R⁰_ _, split, { intros cl, refine ⟨is_fraction_ring.injective _ _, λ x, ⟨cl, _⟩⟩, rintros ⟨y, y_eq⟩, rw ← y_eq, exact is_integral_algebra_map }, { rintros ⟨-, cl⟩ x hx, exact cl.mp hx } en...
theorem
is_integrally_closed_iff_is_integral_closure
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "fraction_ring", "is_integral_algebra_map", "is_integral_closure", "is_integrally_closed", "is_integrally_closed_iff", "is_localization.alg_equiv" ]
`R` is integrally closed iff it is the integral closure of itself in its field of fractions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_iff {x : K} : is_integral R x ↔ ∃ y : R, algebra_map R K y = x
is_integral_closure.is_integral_iff
lemma
is_integrally_closed.is_integral_iff
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_algebra_map_eq_of_is_integral_pow {x : K} {n : ℕ} (hn : 0 < n) (hx : is_integral R $ x ^ n) : ∃ y : R, algebra_map R K y = x
is_integral_iff.mp $ is_integral_of_pow hn hx
lemma
is_integrally_closed.exists_algebra_map_eq_of_is_integral_pow
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "algebra_map", "is_integral", "is_integral_of_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_algebra_map_eq_of_pow_mem_subalgebra {K : Type*} [field K] [algebra R K] {S : subalgebra R K} [is_integrally_closed S] [is_fraction_ring S K] {x : K} {n : ℕ} (hn : 0 < n) (hx : x ^ n ∈ S) : ∃ y : S, algebra_map S K y = x
exists_algebra_map_eq_of_is_integral_pow hn $ is_integral_iff.mpr ⟨⟨x ^ n, hx⟩, rfl⟩
lemma
is_integrally_closed.exists_algebra_map_eq_of_pow_mem_subalgebra
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "algebra", "algebra_map", "field", "is_fraction_ring", "is_integrally_closed", "subalgebra" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_closure_eq_bot_iff : integral_closure R K = ⊥ ↔ is_integrally_closed R
begin refine eq_bot_iff.trans _, split, { rw is_integrally_closed_iff K, intros h x hx, exact set.mem_range.mp (algebra.mem_bot.mp (h hx)), assumption }, { intros h x hx, rw [algebra.mem_bot, set.mem_range], exactI is_integral_iff.mp hx }, end
lemma
is_integrally_closed.integral_closure_eq_bot_iff
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "algebra.mem_bot", "integral_closure", "is_integrally_closed", "is_integrally_closed_iff", "set.mem_range" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_closure_eq_bot : integral_closure R K = ⊥
(integral_closure_eq_bot_iff K).mpr ‹_›
lemma
is_integrally_closed.integral_closure_eq_bot
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "integral_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integrally_closed_of_finite_extension [finite_dimensional K L] : is_integrally_closed (integral_closure R L)
begin letI : is_fraction_ring (integral_closure R L) L := is_fraction_ring_of_finite_extension K L, exact (integral_closure_eq_bot_iff L).mp integral_closure_idem end
lemma
integral_closure.is_integrally_closed_of_finite_extension
ring_theory
src/ring_theory/integrally_closed.lean
[ "ring_theory.integral_closure", "ring_theory.localization.integral" ]
[ "finite_dimensional", "integral_closure", "integral_closure_idem", "is_fraction_ring", "is_integrally_closed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_elem (f : R →+* A) (x : A)
∃ p : R[X], monic p ∧ eval₂ f x p = 0
def
ring_hom.is_integral_elem
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
An element `x` of `A` is said to be integral over `R` with respect to `f` if it is a root of a monic polynomial `p : R[X]` evaluated under `f`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral (f : R →+* A)
∀ x : A, f.is_integral_elem x
def
ring_hom.is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
A ring homomorphism `f : R →+* A` is said to be integral if every element `A` is integral with respect to the map `f`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral (x : A) : Prop
(algebra_map R A).is_integral_elem x
def
is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map" ]
An element `x` of an algebra `A` over a commutative ring `R` is said to be *integral*, if it is a root of some monic polynomial `p : R[X]`. Equivalently, the element is integral over `R` with respect to the induced `algebra_map`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.is_integral : Prop
(algebra_map R A).is_integral
def
algebra.is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
An algebra is integral if every element of the extension is integral over the base ring
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_map {x : R} : f.is_integral_elem (f x)
⟨X - C x, monic_X_sub_C _, by simp⟩
lemma
ring_hom.is_integral_map
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_algebra_map {x : R} : is_integral R (algebra_map R A x)
(algebra_map R A).is_integral_map
theorem
is_integral_algebra_map
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_noetherian (H : is_noetherian R A) (x : A) : is_integral R x
begin let leval : (R[X] →ₗ[R] A) := (aeval x).to_linear_map, let D : ℕ → submodule R A := λ n, (degree_le R n).map leval, let M := well_founded.min (is_noetherian_iff_well_founded.1 H) (set.range D) ⟨_, ⟨0, rfl⟩⟩, have HM : M ∈ set.range D := well_founded.min_mem _ _ _, cases HM with N HN, have HM : ¬M ...
theorem
is_integral_of_noetherian
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral", "is_noetherian", "linear_map.map_sub", "set.range", "submodule", "well_founded.min", "well_founded.min_mem", "well_founded.not_lt_min" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_submodule_noetherian (S : subalgebra R A) (H : is_noetherian R S.to_submodule) (x : A) (hx : x ∈ S) : is_integral R x
begin suffices : is_integral R (show S, from ⟨x, hx⟩), { rcases this with ⟨p, hpm, hpx⟩, replace hpx := congr_arg S.val hpx, refine ⟨p, hpm, eq.trans _ hpx⟩, simp only [aeval_def, eval₂, sum_def], rw S.val.map_sum, refine finset.sum_congr rfl (λ n hn, _), rw [S.val.map_mul, S.val.map_pow, S....
theorem
is_integral_of_submodule_noetherian
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral", "is_integral_of_noetherian", "is_noetherian", "subalgebra", "subtype.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_is_integral {B C F : Type*} [ring B] [ring C] [algebra R B] [algebra A B] [algebra R C] [is_scalar_tower R A B] [algebra A C] [is_scalar_tower R A C] {b : B} [alg_hom_class F A B C] (f : F) (hb : is_integral R b) : is_integral R (f b)
begin obtain ⟨P, hP⟩ := hb, refine ⟨P, hP.1, _⟩, rw [← aeval_def, show (aeval (f b)) P = (aeval (f b)) (P.map (algebra_map R A)), by simp, aeval_alg_hom_apply, aeval_map_algebra_map, aeval_def, hP.2, _root_.map_zero] end
lemma
map_is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "alg_hom_class", "algebra", "algebra_map", "is_integral", "is_scalar_tower", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_map_of_comp_eq_of_is_integral {R S T U : Type*} [comm_ring R] [comm_ring S] [comm_ring T] [comm_ring U] [algebra R S] [algebra T U] (φ : R →+* T) (ψ : S →+* U) (h : (algebra_map T U).comp φ = ψ.comp (algebra_map R S)) {a : S} (ha : is_integral R a) : is_integral T (ψ a)
begin rw [is_integral, ring_hom.is_integral_elem] at ⊢ ha, obtain ⟨p, hp⟩ := ha, refine ⟨p.map φ, hp.left.map _, _⟩, rw [← eval_map, map_map, h, ← map_map, eval_map, eval₂_at_apply, eval_map, hp.right, ring_hom.map_zero], end
lemma
is_integral_map_of_comp_eq_of_is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "algebra_map", "comm_ring", "is_integral", "ring_hom.is_integral_elem", "ring_hom.map_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_alg_hom_iff {A B : Type*} [ring A] [ring B] [algebra R A] [algebra R B] (f : A →ₐ[R] B) (hf : function.injective f) {x : A} : is_integral R (f x) ↔ is_integral R x
begin refine ⟨_, map_is_integral f⟩, rintros ⟨p, hp, hx⟩, use [p, hp], rwa [← f.comp_algebra_map, ← alg_hom.coe_to_ring_hom, ← polynomial.hom_eval₂, alg_hom.coe_to_ring_hom, map_eq_zero_iff f hf] at hx end
theorem
is_integral_alg_hom_iff
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "alg_hom.coe_to_ring_hom", "algebra", "is_integral", "map_is_integral", "polynomial.hom_eval₂", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_alg_equiv {A B : Type*} [ring A] [ring B] [algebra R A] [algebra R B] (f : A ≃ₐ[R] B) {x : A} : is_integral R (f x) ↔ is_integral R x
⟨λ h, by simpa using map_is_integral f.symm.to_alg_hom h, map_is_integral f.to_alg_hom⟩
theorem
is_integral_alg_equiv
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "is_integral", "map_is_integral", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_is_scalar_tower [algebra A B] [is_scalar_tower R A B] {x : B} (hx : is_integral R x) : is_integral A x
let ⟨p, hp, hpx⟩ := hx in ⟨p.map $ algebra_map R A, hp.map _, by rw [← aeval_def, aeval_map_algebra_map, aeval_def, hpx]⟩
theorem
is_integral_of_is_scalar_tower
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "algebra_map", "is_integral", "is_scalar_tower" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_is_integral_int {B C F : Type*} [ring B] [ring C] {b : B} [ring_hom_class F B C] (f : F) (hb : is_integral ℤ b) : is_integral ℤ (f b)
map_is_integral (f : B →+* C).to_int_alg_hom hb
lemma
map_is_integral_int
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral", "map_is_integral", "ring", "ring_hom_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_subring {x : A} (T : subring R) (hx : is_integral T x) : is_integral R x
is_integral_of_is_scalar_tower hx
theorem
is_integral_of_subring
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral", "is_integral_of_is_scalar_tower", "subring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.algebra_map [algebra A B] [is_scalar_tower R A B] {x : A} (h : is_integral R x) : is_integral R (algebra_map A B x)
begin rcases h with ⟨f, hf, hx⟩, use [f, hf], rw [is_scalar_tower.algebra_map_eq R A B, ← hom_eval₂, hx, ring_hom.map_zero] end
lemma
is_integral.algebra_map
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "algebra_map", "is_integral", "is_scalar_tower", "is_scalar_tower.algebra_map_eq", "ring_hom.map_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_algebra_map_iff [algebra A B] [is_scalar_tower R A B] {x : A} (hAB : function.injective (algebra_map A B)) : is_integral R (algebra_map A B x) ↔ is_integral R x
is_integral_alg_hom_iff (is_scalar_tower.to_alg_hom R A B) hAB
lemma
is_integral_algebra_map_iff
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "algebra_map", "is_integral", "is_integral_alg_hom_iff", "is_scalar_tower", "is_scalar_tower.to_alg_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_iff_is_integral_closure_finite {r : A} : is_integral R r ↔ ∃ s : set R, s.finite ∧ is_integral (subring.closure s) r
begin split; intro hr, { rcases hr with ⟨p, hmp, hpr⟩, refine ⟨_, finset.finite_to_set _, p.restriction, monic_restriction.2 hmp, _⟩, rw [← aeval_def, ← aeval_map_algebra_map R r p.restriction, map_restriction, aeval_def, hpr], }, rcases hr with ⟨s, hs, hsr⟩, exact is_integral_of_subring _ hsr end
theorem
is_integral_iff_is_integral_closure_finite
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "finset.finite_to_set", "is_integral", "is_integral_of_subring", "subring.closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fg_adjoin_singleton_of_integral (x : A) (hx : is_integral R x) : (algebra.adjoin R ({x} : set A)).to_submodule.fg
begin rcases hx with ⟨f, hfm, hfx⟩, existsi finset.image ((^) x) (finset.range (nat_degree f + 1)), apply le_antisymm, { rw span_le, intros s hs, rw finset.mem_coe at hs, rcases finset.mem_image.1 hs with ⟨k, hk, rfl⟩, clear hk, exact (algebra.adjoin R {x}).pow_mem (algebra.subset_adjoin (set.mem_single...
theorem
fg_adjoin_singleton_of_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "alg_hom.map_add", "alg_hom.map_mul", "algebra.adjoin", "algebra.adjoin_singleton_eq_range_aeval", "algebra.smul_def", "algebra.subset_adjoin", "finset.image", "finset.mem_coe", "finset.mem_range", "finset.range", "is_integral", "nat.lt_succ_iff", "pow_mem", "set.mem_singleton", "zero_mu...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fg_adjoin_of_finite {s : set A} (hfs : s.finite) (his : ∀ x ∈ s, is_integral R x) : (algebra.adjoin R s).to_submodule.fg
set.finite.induction_on hfs (λ _, ⟨{1}, submodule.ext $ λ x, by { erw [algebra.adjoin_empty, finset.coe_singleton, ← one_eq_span, one_eq_range, linear_map.mem_range, algebra.mem_bot], refl }⟩) (λ a s has hs ih his, by rw [← set.union_singleton, algebra.adjoin_union_coe_submodule]; exact fg.mul (ih $ λ i...
theorem
fg_adjoin_of_finite
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.adjoin", "algebra.adjoin_empty", "algebra.adjoin_union_coe_submodule", "algebra.mem_bot", "fg_adjoin_singleton_of_integral", "finset.coe_singleton", "ih", "is_integral", "linear_map.mem_range", "set.finite.induction_on", "set.mem_insert", "set.mem_insert_of_mem", "set.union_singleto...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_noetherian_adjoin_finset [is_noetherian_ring R] (s : finset A) (hs : ∀ x ∈ s, is_integral R x) : is_noetherian R (algebra.adjoin R (↑s : set A))
is_noetherian_of_fg_of_noetherian _ (fg_adjoin_of_finite s.finite_to_set hs)
lemma
is_noetherian_adjoin_finset
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.adjoin", "fg_adjoin_of_finite", "finset", "is_integral", "is_noetherian", "is_noetherian_of_fg_of_noetherian", "is_noetherian_ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_mem_of_fg (S : subalgebra R A) (HS : S.to_submodule.fg) (x : A) (hx : x ∈ S) : is_integral R x
begin -- say `x ∈ S`. We want to prove that `x` is integral over `R`. -- Say `S` is generated as an `R`-module by the set `y`. cases HS with y hy, -- We can write `x` as `∑ rᵢ yᵢ` for `yᵢ ∈ Y`. obtain ⟨lx, hlx1, hlx2⟩ : ∃ (l : A →₀ R) (H : l ∈ finsupp.supported R R ↑y), (finsupp.total A A R id) l = x, {...
theorem
is_integral_of_mem_of_fg
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "algebra.adjoin", "algebra.algebra_map_eq_smul_one", "algebra.mem_adjoin_iff", "algebra.of_subring", "algebra.subset_adjoin", "algebra_map", "comm_ring", "finset.bUnion", "finset.coe_insert", "finset.finite_to_set", "finset.mem_image_of_mem", "finset.mem_union_left", "finset.mem...
If `S` is a sub-`R`-algebra of `A` and `S` is finitely-generated as an `R`-module, then all elements of `S` are integral over `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
module.End.is_integral {M : Type*} [add_comm_group M] [module R M] [module.finite R M] : algebra.is_integral R (module.End R M)
linear_map.exists_monic_and_aeval_eq_zero R
lemma
module.End.is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "add_comm_group", "algebra.is_integral", "linear_map.exists_monic_and_aeval_eq_zero", "module", "module.End", "module.finite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_smul_mem_submodule {M : Type*} [add_comm_group M] [module R M] [module A M] [is_scalar_tower R A M] [no_zero_smul_divisors A M] (N : submodule R M) (hN : N ≠ ⊥) (hN' : N.fg) (x : A) (hx : ∀ n ∈ N, x • n ∈ N) : is_integral R x
begin let A' : subalgebra R A := { carrier := { x | ∀ n ∈ N, x • n ∈ N }, mul_mem' := λ a b ha hb n hn, smul_smul a b n ▸ ha _ (hb _ hn), one_mem' := λ n hn, (one_smul A n).symm ▸ hn, add_mem' := λ a b ha hb n hn, (add_smul a b n).symm ▸ N.add_mem (ha _ hn) (hb _ hn), zero_mem' := λ n hn, (zero_smul...
lemma
is_integral_of_smul_mem_submodule
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "add_comm_group", "add_smul", "alg_hom.of_linear_map", "algebra_map_smul", "by_contra", "distrib_mul_action.to_linear_map", "eq_bot_iff", "is_integral", "is_integral_alg_hom_iff", "is_scalar_tower", "linear_map.congr_fun", "linear_map.ext", "linear_map.ker_eq_bot", "module", "module.End"...
Suppose `A` is an `R`-algebra, `M` is an `A`-module such that `a • m ≠ 0` for all non-zero `a` and `m`. If `x : A` fixes a nontrivial f.g. `R`-submodule `N` of `M`, then `x` is `R`-integral.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.finite.to_is_integral (h : f.finite) : f.is_integral
by { letI := f.to_algebra, exact λ x, is_integral_of_mem_of_fg ⊤ h.1 _ trivial }
lemma
ring_hom.finite.to_is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral_of_mem_of_fg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral.to_finite (h : f.is_integral) (h' : f.finite_type) : f.finite
begin letI := f.to_algebra, unfreezingI { obtain ⟨s, hs⟩ := h' }, constructor, change (⊤ : subalgebra R S).to_submodule.fg, rw ← hs, exact fg_adjoin_of_finite (set.to_finite _) (λ x _, h x) end
lemma
ring_hom.is_integral.to_finite
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "fg_adjoin_of_finite", "set.to_finite", "subalgebra" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.finite_iff_is_integral_and_finite_type : f.finite ↔ f.is_integral ∧ f.finite_type
⟨λ h, ⟨h.to_is_integral, h.to_finite_type⟩, λ ⟨h, h'⟩, h.to_finite h'⟩
lemma
ring_hom.finite_iff_is_integral_and_finite_type
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
finite = integral + finite type
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.is_integral.finite (h : algebra.is_integral R A) [h' : algebra.finite_type R A] : module.finite R A
begin have := h.to_finite (by { delta ring_hom.finite_type, convert h', ext, exact (algebra.smul_def _ _).symm }), delta ring_hom.finite at this, convert this, ext, exact algebra.smul_def _ _, end
lemma
algebra.is_integral.finite
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.finite_type", "algebra.is_integral", "algebra.smul_def", "module.finite", "ring_hom.finite", "ring_hom.finite_type" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.is_integral.of_finite [h : module.finite R A] : algebra.is_integral R A
begin apply ring_hom.finite.to_is_integral, delta ring_hom.finite, convert h, ext, exact (algebra.smul_def _ _).symm, end
lemma
algebra.is_integral.of_finite
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.is_integral", "algebra.smul_def", "module.finite", "ring_hom.finite", "ring_hom.finite.to_is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.finite_iff_is_integral_and_finite_type : module.finite R A ↔ algebra.is_integral R A ∧ algebra.finite_type R A
⟨λ h, by exactI ⟨algebra.is_integral.of_finite, infer_instance⟩, λ ⟨h, h'⟩, by exactI h.finite⟩
lemma
algebra.finite_iff_is_integral_and_finite_type
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.finite_type", "algebra.is_integral", "module.finite" ]
finite = integral + finite type
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_of_mem_closure {x y z : S} (hx : f.is_integral_elem x) (hy : f.is_integral_elem y) (hz : z ∈ subring.closure ({x, y} : set S)) : f.is_integral_elem z
begin letI : algebra R S := f.to_algebra, have := (fg_adjoin_singleton_of_integral x hx).mul (fg_adjoin_singleton_of_integral y hy), rw [← algebra.adjoin_union_coe_submodule, set.singleton_union] at this, exact is_integral_of_mem_of_fg (algebra.adjoin R {x, y}) this z (algebra.mem_adjoin_iff.2 $ subring.clo...
lemma
ring_hom.is_integral_of_mem_closure
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "algebra.adjoin", "algebra.adjoin_union_coe_submodule", "fg_adjoin_singleton_of_integral", "is_integral_of_mem_of_fg", "set.singleton_union", "set.subset_union_right", "subring.closure", "subring.closure_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_mem_closure {x y z : A} (hx : is_integral R x) (hy : is_integral R y) (hz : z ∈ subring.closure ({x, y} : set A)) : is_integral R z
(algebra_map R A).is_integral_of_mem_closure hx hy hz
theorem
is_integral_of_mem_closure
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral", "subring.closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_zero : f.is_integral_elem 0
f.map_zero ▸ f.is_integral_map
lemma
ring_hom.is_integral_zero
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_zero : is_integral R (0:A)
(algebra_map R A).is_integral_zero
theorem
is_integral_zero
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_one : f.is_integral_elem 1
f.map_one ▸ f.is_integral_map
lemma
ring_hom.is_integral_one
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_one : is_integral R (1:A)
(algebra_map R A).is_integral_one
theorem
is_integral_one
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_add {x y : S} (hx : f.is_integral_elem x) (hy : f.is_integral_elem y) : f.is_integral_elem (x + y)
f.is_integral_of_mem_closure hx hy $ subring.add_mem _ (subring.subset_closure (or.inl rfl)) (subring.subset_closure (or.inr rfl))
lemma
ring_hom.is_integral_add
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "subring.add_mem", "subring.subset_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_add {x y : A} (hx : is_integral R x) (hy : is_integral R y) : is_integral R (x + y)
(algebra_map R A).is_integral_add hx hy
theorem
is_integral_add
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_neg {x : S} (hx : f.is_integral_elem x) : f.is_integral_elem (-x)
f.is_integral_of_mem_closure hx hx (subring.neg_mem _ (subring.subset_closure (or.inl rfl)))
lemma
ring_hom.is_integral_neg
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "subring.neg_mem", "subring.subset_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_neg {x : A} (hx : is_integral R x) : is_integral R (-x)
(algebra_map R A).is_integral_neg hx
theorem
is_integral_neg
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_sub {x y : S} (hx : f.is_integral_elem x) (hy : f.is_integral_elem y) : f.is_integral_elem (x - y)
by simpa only [sub_eq_add_neg] using f.is_integral_add hx (f.is_integral_neg hy)
lemma
ring_hom.is_integral_sub
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_sub {x y : A} (hx : is_integral R x) (hy : is_integral R y) : is_integral R (x - y)
(algebra_map R A).is_integral_sub hx hy
theorem
is_integral_sub
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_mul {x y : S} (hx : f.is_integral_elem x) (hy : f.is_integral_elem y) : f.is_integral_elem (x * y)
f.is_integral_of_mem_closure hx hy (subring.mul_mem _ (subring.subset_closure (or.inl rfl)) (subring.subset_closure (or.inr rfl)))
lemma
ring_hom.is_integral_mul
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "subring.mul_mem", "subring.subset_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_mul {x y : A} (hx : is_integral R x) (hy : is_integral R y) : is_integral R (x * y)
(algebra_map R A).is_integral_mul hx hy
theorem
is_integral_mul
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_smul [algebra S A] [algebra R S] [is_scalar_tower R S A] {x : A} (r : R) (hx : is_integral S x) : is_integral S (r • x)
begin rw [algebra.smul_def, is_scalar_tower.algebra_map_apply R S A], exact is_integral_mul is_integral_algebra_map hx, end
lemma
is_integral_smul
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra", "algebra.smul_def", "is_integral", "is_integral_algebra_map", "is_integral_mul", "is_scalar_tower", "is_scalar_tower.algebra_map_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_pow {x : A} {n : ℕ} (hn : 0 < n) (hx : is_integral R $ x ^ n) : is_integral R x
begin rcases hx with ⟨p, ⟨hmonic, heval⟩⟩, exact ⟨expand R n p, monic.expand hn hmonic, by rwa [eval₂_eq_eval_map, map_expand, expand_eval, ← eval₂_eq_eval_map]⟩ end
lemma
is_integral_of_pow
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_closure : subalgebra R A
{ carrier := { r | is_integral R r }, zero_mem' := is_integral_zero, one_mem' := is_integral_one, add_mem' := λ _ _, is_integral_add, mul_mem' := λ _ _, is_integral_mul, algebra_map_mem' := λ x, is_integral_algebra_map }
def
integral_closure
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral", "is_integral_add", "is_integral_algebra_map", "is_integral_mul", "is_integral_one", "is_integral_zero", "subalgebra" ]
The integral closure of R in an R-algebra A.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_integral_closure_iff_mem_fg {r : A} : r ∈ integral_closure R A ↔ ∃ M : subalgebra R A, M.to_submodule.fg ∧ r ∈ M
⟨λ hr, ⟨algebra.adjoin R {r}, fg_adjoin_singleton_of_integral _ hr, algebra.subset_adjoin rfl⟩, λ ⟨M, Hf, hrM⟩, is_integral_of_mem_of_fg M Hf _ hrM⟩
theorem
mem_integral_closure_iff_mem_fg
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.subset_adjoin", "fg_adjoin_singleton_of_integral", "integral_closure", "is_integral_of_mem_of_fg", "subalgebra" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
adjoin_le_integral_closure {x : A} (hx : is_integral R x) : algebra.adjoin R {x} ≤ integral_closure R A
begin rw [algebra.adjoin_le_iff], simp only [set_like.mem_coe, set.singleton_subset_iff], exact hx end
lemma
adjoin_le_integral_closure
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.adjoin", "algebra.adjoin_le_iff", "integral_closure", "is_integral", "set.singleton_subset_iff", "set_like.mem_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_integral_closure_iff_is_integral {S : subalgebra R A} : S ≤ integral_closure R A ↔ algebra.is_integral R S
set_like.forall.symm.trans (forall_congr (λ x, show is_integral R (algebra_map S A x) ↔ is_integral R x, from is_integral_algebra_map_iff subtype.coe_injective))
lemma
le_integral_closure_iff_is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.is_integral", "algebra_map", "integral_closure", "is_integral", "is_integral_algebra_map_iff", "subalgebra", "subtype.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_sup {S T : subalgebra R A} : algebra.is_integral R ↥(S ⊔ T) ↔ algebra.is_integral R S ∧ algebra.is_integral R T
by simp only [←le_integral_closure_iff_is_integral, sup_le_iff]
lemma
is_integral_sup
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.is_integral", "subalgebra", "sup_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_closure_map_alg_equiv (f : A ≃ₐ[R] B) : (integral_closure R A).map (f : A →ₐ[R] B) = integral_closure R B
begin ext y, rw subalgebra.mem_map, split, { rintros ⟨x, hx, rfl⟩, exact map_is_integral f hx }, { intro hy, use [f.symm y, map_is_integral (f.symm : B →ₐ[R] A) hy], simp } end
lemma
integral_closure_map_alg_equiv
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "integral_closure", "map_is_integral", "subalgebra.mem_map" ]
Mapping an integral closure along an `alg_equiv` gives the integral closure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
integral_closure.is_integral (x : integral_closure R A) : is_integral R x
let ⟨p, hpm, hpx⟩ := x.2 in ⟨p, hpm, subtype.eq $ by rwa [← aeval_def, subtype.val_eq_coe, ← subalgebra.val_apply, aeval_alg_hom_apply] at hpx⟩
lemma
integral_closure.is_integral
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "integral_closure", "is_integral", "subalgebra.val_apply", "subtype.val_eq_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_hom.is_integral_of_is_integral_mul_unit (x y : S) (r : R) (hr : f r * y = 1) (hx : f.is_integral_elem (x * y)) : f.is_integral_elem x
begin obtain ⟨p, ⟨p_monic, hp⟩⟩ := hx, refine ⟨scale_roots p r, ⟨(monic_scale_roots_iff r).2 p_monic, _⟩⟩, convert scale_roots_eval₂_eq_zero f hp, rw [mul_comm x y, ← mul_assoc, hr, one_mul], end
lemma
ring_hom.is_integral_of_is_integral_mul_unit
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "mul_assoc", "mul_comm", "one_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_is_integral_mul_unit {x y : A} {r : R} (hr : algebra_map R A r * y = 1) (hx : is_integral R (x * y)) : is_integral R x
(algebra_map R A).is_integral_of_is_integral_mul_unit x y r hr hx
theorem
is_integral_of_is_integral_mul_unit
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra_map", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_mem_closure' (G : set A) (hG : ∀ x ∈ G, is_integral R x) : ∀ x ∈ (subring.closure G), is_integral R x
λ x hx, subring.closure_induction hx hG is_integral_zero is_integral_one (λ _ _, is_integral_add) (λ _, is_integral_neg) (λ _ _, is_integral_mul)
lemma
is_integral_of_mem_closure'
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral", "is_integral_add", "is_integral_mul", "is_integral_neg", "is_integral_one", "is_integral_zero", "subring.closure", "subring.closure_induction" ]
Generalization of `is_integral_of_mem_closure` bootstrapped up from that lemma
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral_of_mem_closure'' {S : Type*} [comm_ring S] {f : R →+* S} (G : set S) (hG : ∀ x ∈ G, f.is_integral_elem x) : ∀ x ∈ (subring.closure G), f.is_integral_elem x
λ x hx, @is_integral_of_mem_closure' R S _ _ f.to_algebra G hG x hx
lemma
is_integral_of_mem_closure''
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "comm_ring", "is_integral_of_mem_closure'", "subring.closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.pow {x : A} (h : is_integral R x) (n : ℕ) : is_integral R (x ^ n)
(integral_closure R A).pow_mem h n
lemma
is_integral.pow
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "integral_closure", "is_integral", "pow_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.nsmul {x : A} (h : is_integral R x) (n : ℕ) : is_integral R (n • x)
(integral_closure R A).nsmul_mem h n
lemma
is_integral.nsmul
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "integral_closure", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.zsmul {x : A} (h : is_integral R x) (n : ℤ) : is_integral R (n • x)
(integral_closure R A).zsmul_mem h n
lemma
is_integral.zsmul
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "integral_closure", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.multiset_prod {s : multiset A} (h : ∀ x ∈ s, is_integral R x) : is_integral R s.prod
(integral_closure R A).multiset_prod_mem h
lemma
is_integral.multiset_prod
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "integral_closure", "is_integral", "multiset", "multiset_prod_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.multiset_sum {s : multiset A} (h : ∀ x ∈ s, is_integral R x) : is_integral R s.sum
(integral_closure R A).multiset_sum_mem h
lemma
is_integral.multiset_sum
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "integral_closure", "is_integral", "multiset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.prod {α : Type*} {s : finset α} (f : α → A) (h : ∀ x ∈ s, is_integral R (f x)) : is_integral R (∏ x in s, f x)
(integral_closure R A).prod_mem h
lemma
is_integral.prod
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "finset", "integral_closure", "is_integral", "prod_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.sum {α : Type*} {s : finset α} (f : α → A) (h : ∀ x ∈ s, is_integral R (f x)) : is_integral R (∑ x in s, f x)
(integral_closure R A).sum_mem h
lemma
is_integral.sum
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "finset", "integral_closure", "is_integral" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.det {n : Type*} [fintype n] [decidable_eq n] {M : matrix n n A} (h : ∀ i j, is_integral R (M i j)) : is_integral R M.det
begin rw [matrix.det_apply], exact is_integral.sum _ (λ σ hσ, is_integral.zsmul (is_integral.prod _ (λ i hi, h _ _)) _) end
lemma
is_integral.det
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "fintype", "is_integral", "is_integral.prod", "is_integral.sum", "is_integral.zsmul", "matrix", "matrix.det_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.pow_iff {x : A} {n : ℕ} (hn : 0 < n) : is_integral R (x ^ n) ↔ is_integral R x
⟨is_integral_of_pow hn, λ hx, is_integral.pow hx n⟩
lemma
is_integral.pow_iff
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "is_integral", "is_integral.pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_integral.tmul (x : A) {y : B} (h : is_integral R y) : is_integral A (x ⊗ₜ[R] y)
begin obtain ⟨p, hp, hp'⟩ := h, refine ⟨(p.map (algebra_map R A)).scale_roots x, _, _⟩, { rw polynomial.monic_scale_roots_iff, exact hp.map _ }, convert @polynomial.scale_roots_eval₂_mul (A ⊗[R] B) A _ _ _ algebra.tensor_product.include_left.to_ring_hom (1 ⊗ₜ y) x using 2, { simp only [alg_hom.to_ring_hom...
lemma
is_integral.tmul
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "alg_hom.coe_to_ring_hom", "alg_hom.to_ring_hom_eq_coe", "algebra.tensor_product.include_left_apply", "algebra.tensor_product.include_left_comp_algebra_map", "algebra.tensor_product.tmul_mul_tmul", "algebra_map", "is_integral", "mul_one", "mul_zero", "one_mul", "polynomial.eval_map", "polynomi...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_scale_roots (p : R[X]) : R[X]
∑ i in p.support, monomial i (if i = p.nat_degree then 1 else p.coeff i * p.leading_coeff ^ (p.nat_degree - 1 - i))
def
normalize_scale_roots
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[]
The monic polynomial whose roots are `p.leading_coeff * x` for roots `x` of `p`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_scale_roots_coeff_mul_leading_coeff_pow (i : ℕ) (hp : 1 ≤ nat_degree p) : (normalize_scale_roots p).coeff i * p.leading_coeff ^ i = p.coeff i * p.leading_coeff ^ (p.nat_degree - 1)
begin simp only [normalize_scale_roots, finset_sum_coeff, coeff_monomial, finset.sum_ite_eq', one_mul, zero_mul, mem_support_iff, ite_mul, ne.def, ite_not], split_ifs with h₁ h₂, { simp [h₁], }, { rw [h₂, leading_coeff, ← pow_succ, tsub_add_cancel_of_le hp], }, { rw [mul_assoc, ← pow_add, tsub_add_cancel_...
lemma
normalize_scale_roots_coeff_mul_leading_coeff_pow
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "ite_mul", "ite_not", "lt_iff_le_and_ne", "mul_assoc", "nat.le_pred_of_lt", "normalize_scale_roots", "one_mul", "pow_add", "pow_succ", "tsub_add_cancel_of_le", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
leading_coeff_smul_normalize_scale_roots (p : R[X]) : p.leading_coeff • normalize_scale_roots p = scale_roots p p.leading_coeff
begin ext, simp only [coeff_scale_roots, normalize_scale_roots, coeff_monomial, coeff_smul, finset.smul_sum, ne.def, finset.sum_ite_eq', finset_sum_coeff, smul_ite, smul_zero, mem_support_iff], split_ifs with h₁ h₂, { simp [*] }, { simp [*] }, { rw [algebra.id.smul_eq_mul, mul_comm, mul_assoc, ← pow_suc...
lemma
leading_coeff_smul_normalize_scale_roots
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "algebra.id.smul_eq_mul", "finset.smul_sum", "mul_assoc", "mul_comm", "nat.succ_le_iff", "normalize_scale_roots", "pow_succ'", "smul_ite", "smul_zero", "tsub_add_cancel_of_le", "tsub_pos_of_lt", "tsub_right_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_scale_roots_support : (normalize_scale_roots p).support ≤ p.support
begin intro x, contrapose, simp only [not_mem_support_iff, normalize_scale_roots, finset_sum_coeff, coeff_monomial, finset.sum_ite_eq', mem_support_iff, ne.def, not_not, ite_eq_right_iff], intros h₁ h₂, exact (h₂ h₁).rec _, end
lemma
normalize_scale_roots_support
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "ite_eq_right_iff", "normalize_scale_roots", "not_not" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_scale_roots_degree : (normalize_scale_roots p).degree = p.degree
begin apply le_antisymm, { exact finset.sup_mono (normalize_scale_roots_support p) }, { rw [← degree_scale_roots, ← leading_coeff_smul_normalize_scale_roots], exact degree_smul_le _ _ } end
lemma
normalize_scale_roots_degree
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "finset.sup_mono", "leading_coeff_smul_normalize_scale_roots", "normalize_scale_roots", "normalize_scale_roots_support" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
normalize_scale_roots_eval₂_leading_coeff_mul (h : 1 ≤ p.nat_degree) (f : R →+* S) (x : S) : (normalize_scale_roots p).eval₂ f (f p.leading_coeff * x) = f p.leading_coeff ^ (p.nat_degree - 1) * (p.eval₂ f x)
begin rw [eval₂_eq_sum_range, eval₂_eq_sum_range, finset.mul_sum], apply finset.sum_congr, { rw nat_degree_eq_of_degree_eq (normalize_scale_roots_degree p) }, intros n hn, rw [mul_pow, ← mul_assoc, ← f.map_pow, ← f.map_mul, normalize_scale_roots_coeff_mul_leading_coeff_pow _ _ h, f.map_mul, f.map_pow], ...
lemma
normalize_scale_roots_eval₂_leading_coeff_mul
ring_theory
src/ring_theory/integral_closure.lean
[ "data.polynomial.expand", "linear_algebra.finite_dimensional", "linear_algebra.matrix.charpoly.linear_map", "ring_theory.adjoin.fg", "ring_theory.finite_type", "ring_theory.polynomial.scale_roots", "ring_theory.polynomial.tower", "ring_theory.tensor_product" ]
[ "finset.mul_sum", "mul_assoc", "mul_pow", "normalize_scale_roots", "normalize_scale_roots_coeff_mul_leading_coeff_pow", "normalize_scale_roots_degree", "ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83