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multiplicity_prime_eq_multiplicity_image_by_factor_order_iso [decidable_eq (associates M)] {m p : associates M} {n : associates N} (hn : n ≠ 0) (hp : p ∈ normalized_factors m) (d : set.Iic m ≃o set.Iic n) : multiplicity p m = multiplicity ↑(d ⟨p, dvd_of_mem_normalized_factors hp⟩) n
begin refine le_antisymm (multiplicity_prime_le_multiplicity_image_by_factor_order_iso hp d) _, suffices : multiplicity ↑(d ⟨p, dvd_of_mem_normalized_factors hp⟩) n ≤ multiplicity ↑(d.symm (d ⟨p, dvd_of_mem_normalized_factors hp⟩)) m, { rw [d.symm_apply_apply ⟨p, dvd_of_mem_normalized_factors hp⟩, subtype.coe...
lemma
multiplicity_prime_eq_multiplicity_image_by_factor_order_iso
ring_theory
src/ring_theory/chain_of_divisors.lean
[ "algebra.is_prime_pow", "algebra.squarefree", "order.hom.bounded", "algebra.gcd_monoid.basic" ]
[ "associates", "classical.dec_eq", "mem_normalized_factors_factor_order_iso_of_mem_normalized_factors", "multiplicity", "multiplicity_prime_le_multiplicity_image_by_factor_order_iso", "set.Iic", "subtype.coe_eta", "subtype.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_factor_order_iso_of_factor_dvd_equiv {m : M} {n : N} {d : {l : M // l ∣ m} ≃ {l : N // l ∣ n}} (hd : ∀ l l', ((d l) : N) ∣ (d l') ↔ (l : M) ∣ (l' : M)) : set.Iic (associates.mk m) ≃o set.Iic (associates.mk n)
{ to_fun := λ l, ⟨associates.mk (d ⟨associates_equiv_of_unique_units ↑l, by { obtain ⟨x, hx⟩ := l, rw [subtype.coe_mk, associates_equiv_of_unique_units_apply, out_dvd_iff], exact hx } ⟩), mk_le_mk_iff_dvd_iff.mpr (subtype.prop (d ⟨associates_equiv_of_unique_units ↑l, _ ⟩)) ⟩, inv_fun := λ l, ⟨associate...
def
mk_factor_order_iso_of_factor_dvd_equiv
ring_theory
src/ring_theory/chain_of_divisors.lean
[ "algebra.is_prime_pow", "algebra.squarefree", "order.hom.bounded", "algebra.gcd_monoid.basic" ]
[ "associates.mk", "associates.mk_le_mk_iff_dvd_iff", "associates_equiv_of_unique_units", "equiv.apply_symm_apply", "equiv.coe_fn_mk", "equiv.symm_apply_apply", "inv_fun", "normalize_eq", "set.Iic", "subtype.coe_eta", "subtype.coe_mk", "subtype.mk_le_mk", "subtype.prop" ]
The order isomorphism between the factors of `mk m` and the factors of `mk n` induced by a bijection between the factors of `m` and the factors of `n` that preserves `∣`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_normalized_factors_factor_dvd_iso_of_mem_normalized_factors [decidable_eq N] {m p : M} {n : N} (hm : m ≠ 0) (hn : n ≠ 0) (hp : p ∈ normalized_factors m) {d : {l : M // l ∣ m} ≃ {l : N // l ∣ n}} (hd : ∀ l l', ((d l) : N) ∣ (d l') ↔ (l : M) ∣ (l' : M)) : ↑(d ⟨p, dvd_of_mem_normalized_factors hp⟩) ∈ normali...
begin suffices : prime ↑(d ⟨associates_equiv_of_unique_units (associates_equiv_of_unique_units.symm p), by simp [dvd_of_mem_normalized_factors hp]⟩), { simp only [associates_equiv_of_unique_units_apply, out_mk, normalize_eq, associates_equiv_of_unique_units_symm_apply] at this, obtain ⟨q, hq, hq'⟩ := ...
lemma
mem_normalized_factors_factor_dvd_iso_of_mem_normalized_factors
ring_theory
src/ring_theory/chain_of_divisors.lean
[ "algebra.is_prime_pow", "algebra.squarefree", "order.hom.bounded", "algebra.gcd_monoid.basic" ]
[ "associates", "associates.mk", "associates.prime_mk", "classical.dec_eq", "irreducible", "map_prime_of_factor_order_iso", "mk_factor_order_iso_of_factor_dvd_equiv", "normalize_eq", "prime", "subtype.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
multiplicity_factor_dvd_iso_eq_multiplicity_of_mem_normalized_factor {m p : M} {n : N} (hm : m ≠ 0) (hn : n ≠ 0) (hp : p ∈ normalized_factors m) {d : {l : M // l ∣ m} ≃ {l : N // l ∣ n}} (hd : ∀ l l', ((d l) : N) ∣ (d l') ↔ (l : M) ∣ l') : multiplicity ((d ⟨p, dvd_of_mem_normalized_factors hp⟩) : N) n = multipl...
begin apply eq.symm, suffices : multiplicity (associates.mk p) (associates.mk m) = multiplicity (associates.mk ↑(d ⟨associates_equiv_of_unique_units (associates_equiv_of_unique_units.symm p), by simp [dvd_of_mem_normalized_factors hp]⟩)) (associates.mk n), { simpa only [multiplicity_mk_eq_multiplici...
lemma
multiplicity_factor_dvd_iso_eq_multiplicity_of_mem_normalized_factor
ring_theory
src/ring_theory/chain_of_divisors.lean
[ "algebra.is_prime_pow", "algebra.squarefree", "order.hom.bounded", "algebra.gcd_monoid.basic" ]
[ "associates", "associates.mk", "classical.dec_eq", "irreducible", "mk_factor_order_iso_of_factor_dvd_equiv", "multiplicity", "multiplicity_prime_eq_multiplicity_image_by_factor_order_iso", "normalize_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_principal_ideal : Kˣ →* (fractional_ideal R⁰ K)ˣ
{ to_fun := λ x, ⟨span_singleton _ x, span_singleton _ x⁻¹, by simp only [span_singleton_one, units.mul_inv', span_singleton_mul_span_singleton], by simp only [span_singleton_one, units.inv_mul', span_singleton_mul_span_singleton]⟩, map_mul' := λ x y, ext (by simp only [units.coe_mk, units.coe_mul, spa...
def
to_principal_ideal
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "fractional_ideal", "units.coe_mk", "units.coe_mul", "units.coe_one", "units.inv_mul'", "units.mul_inv'" ]
`to_principal_ideal R K x` sends `x ≠ 0 : K` to the fractional `R`-ideal generated by `x`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_to_principal_ideal (x : Kˣ) : (to_principal_ideal R K x : fractional_ideal R⁰ K) = span_singleton _ x
by { simp only [to_principal_ideal], refl }
lemma
coe_to_principal_ideal
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "fractional_ideal", "to_principal_ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_principal_ideal_eq_iff {I : (fractional_ideal R⁰ K)ˣ} {x : Kˣ} : to_principal_ideal R K x = I ↔ span_singleton R⁰ (x : K) = I
by { simp only [to_principal_ideal], exact units.ext_iff }
lemma
to_principal_ideal_eq_iff
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "fractional_ideal", "to_principal_ideal", "units.ext_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_principal_ideals_iff {I : (fractional_ideal R⁰ K)ˣ} : I ∈ (to_principal_ideal R K).range ↔ ∃ x : K, span_singleton R⁰ x = I
begin simp only [monoid_hom.mem_range, to_principal_ideal_eq_iff], split; rintros ⟨x, hx⟩, { exact ⟨x, hx⟩ }, { refine ⟨units.mk0 x _, hx⟩, rintro rfl, simpa [I.ne_zero.symm] using hx } end
lemma
mem_principal_ideals_iff
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "fractional_ideal", "monoid_hom.mem_range", "to_principal_ideal", "to_principal_ideal_eq_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
principal_ideals.normal : (to_principal_ideal R K).range.normal
subgroup.normal_of_comm _
instance
principal_ideals.normal
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "subgroup.normal_of_comm", "to_principal_ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group
(fractional_ideal R⁰ (fraction_ring R))ˣ ⧸ (to_principal_ideal R (fraction_ring R)).range
def
class_group
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "fraction_ring", "fractional_ideal", "to_principal_ideal" ]
The ideal class group of `R` is the group of invertible fractional ideals modulo the principal ideals.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk : (fractional_ideal R⁰ K)ˣ →* class_group R
(quotient_group.mk' (to_principal_ideal R (fraction_ring R)).range).comp (units.map (fractional_ideal.canonical_equiv R⁰ K (fraction_ring R)))
def
class_group.mk
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group", "fraction_ring", "fractional_ideal", "fractional_ideal.canonical_equiv", "quotient_group.mk'", "to_principal_ideal", "units.map" ]
Send a nonzero fractional ideal to the corresponding class in the class group.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk_eq_mk {I J : (fractional_ideal R⁰ $ fraction_ring R)ˣ} : class_group.mk I = class_group.mk J ↔ ∃ x : (fraction_ring R)ˣ, I * to_principal_ideal R (fraction_ring R) x = J
by { erw [quotient_group.mk'_eq_mk', canonical_equiv_self, units.map_id, set.exists_range_iff], refl }
lemma
class_group.mk_eq_mk
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.mk", "fraction_ring", "fractional_ideal", "quotient_group.mk'_eq_mk'", "set.exists_range_iff", "to_principal_ideal", "units.map_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk_eq_mk_of_coe_ideal {I J : (fractional_ideal R⁰ $ fraction_ring R)ˣ} {I' J' : ideal R} (hI : (I : fractional_ideal R⁰ $ fraction_ring R) = I') (hJ : (J : fractional_ideal R⁰ $ fraction_ring R) = J') : class_group.mk I = class_group.mk J ↔ ∃ x y : R, x ≠ 0 ∧ y ≠ 0 ∧ ideal.span {x} * I' = ideal....
begin rw [class_group.mk_eq_mk], split, { rintro ⟨x, rfl⟩, rw [units.coe_mul, hI, coe_to_principal_ideal, mul_comm, span_singleton_mul_coe_ideal_eq_coe_ideal] at hJ, exact ⟨_, _, sec_fst_ne_zero le_rfl x.ne_zero, sec_snd_ne_zero le_rfl ↑x, hJ⟩ }, { rintro ⟨x, y, hx, hy, h⟩, split, rw [mul_co...
lemma
class_group.mk_eq_mk_of_coe_ideal
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.mk", "class_group.mk_eq_mk", "coe_to_principal_ideal", "fraction_ring", "fractional_ideal", "ideal", "ideal.span", "le_rfl", "mem_non_zero_divisors_of_ne_zero", "mul_comm", "units.coe_mul", "units.eq_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk_eq_one_of_coe_ideal {I : (fractional_ideal R⁰ $ fraction_ring R)ˣ} {I' : ideal R} (hI : (I : fractional_ideal R⁰ $ fraction_ring R) = I') : class_group.mk I = 1 ↔ ∃ x : R, x ≠ 0 ∧ I' = ideal.span {x}
begin rw [← map_one class_group.mk, class_group.mk_eq_mk_of_coe_ideal hI (_ : _ = ↑⊤)], any_goals { refl }, split, { rintro ⟨x, y, hx, hy, h⟩, rw [ideal.mul_top] at h, rcases ideal.mem_span_singleton_mul.mp ((ideal.span_singleton_le_iff_mem _).mp h.ge) with ⟨i, hi, rfl⟩, rw [← ideal.span_singl...
lemma
class_group.mk_eq_one_of_coe_ideal
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.mk", "class_group.mk_eq_mk_of_coe_ideal", "fraction_ring", "fractional_ideal", "ideal", "ideal.mul_top", "ideal.span", "ideal.span_singleton_le_iff_mem", "ideal.span_singleton_mul_right_inj", "ideal.span_singleton_mul_span_singleton", "ideal.span_singleton_one", "ideal.top_mul", ...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.induction {P : class_group R → Prop} (h : ∀ (I : (fractional_ideal R⁰ K)ˣ), P (class_group.mk I)) (x : class_group R) : P x
quotient_group.induction_on x (λ I, begin convert h (units.map_equiv ↑(canonical_equiv R⁰ (fraction_ring R) K) I), ext : 1, rw [units.coe_map, units.coe_map_equiv], exact (canonical_equiv_flip R⁰ K (fraction_ring R) I).symm end)
lemma
class_group.induction
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group", "class_group.mk", "fraction_ring", "fractional_ideal", "quotient_group.induction_on", "units.coe_map", "units.coe_map_equiv", "units.map_equiv" ]
Induction principle for the class group: to show something holds for all `x : class_group R`, we can choose a fraction field `K` and show it holds for the equivalence class of each `I : fractional_ideal R⁰ K`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.equiv : class_group R ≃* (fractional_ideal R⁰ K)ˣ ⧸ (to_principal_ideal R K).range
quotient_group.congr _ _ (units.map_equiv (fractional_ideal.canonical_equiv R⁰ (fraction_ring R) K : fractional_ideal R⁰ (fraction_ring R) ≃* fractional_ideal R⁰ K)) $ begin ext I, simp only [subgroup.mem_map, mem_principal_ideals_iff, monoid_hom.coe_coe], split, { rintro ⟨I, ⟨x, hx⟩, rfl⟩, refine ⟨fr...
def
class_group.equiv
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group", "fraction_ring", "fraction_ring.alg_equiv", "fractional_ideal", "fractional_ideal.canonical_equiv", "mem_principal_ideals_iff", "monoid_hom.coe_coe", "quotient_group.congr", "ring_equiv.coe_to_mul_equiv", "subgroup.mem_map", "to_principal_ideal", "units.coe_map_equiv", "units....
The definition of the class group does not depend on the choice of field of fractions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.equiv_mk (K' : Type*) [field K'] [algebra R K'] [is_fraction_ring R K'] (I : (fractional_ideal R⁰ K)ˣ) : class_group.equiv K' (class_group.mk I) = quotient_group.mk' _ (units.map_equiv ↑(fractional_ideal.canonical_equiv R⁰ K K') I)
begin rw [class_group.equiv, class_group.mk, monoid_hom.comp_apply, quotient_group.congr_mk'], congr, ext : 1, rw [units.coe_map_equiv, units.coe_map_equiv, units.coe_map], exact fractional_ideal.canonical_equiv_canonical_equiv _ _ _ _ _ end
lemma
class_group.equiv_mk
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "algebra", "class_group.equiv", "class_group.mk", "field", "fractional_ideal", "fractional_ideal.canonical_equiv", "fractional_ideal.canonical_equiv_canonical_equiv", "is_fraction_ring", "monoid_hom.comp_apply", "quotient_group.congr_mk'", "quotient_group.mk'", "units.coe_map", "units.coe_ma...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk_canonical_equiv (K' : Type*) [field K'] [algebra R K'] [is_fraction_ring R K'] (I : (fractional_ideal R⁰ K)ˣ) : class_group.mk (units.map ↑(canonical_equiv R⁰ K K') I : (fractional_ideal R⁰ K')ˣ) = class_group.mk I
by rw [class_group.mk, monoid_hom.comp_apply, ← monoid_hom.comp_apply (units.map _), ← units.map_comp, ← ring_equiv.coe_monoid_hom_trans, fractional_ideal.canonical_equiv_trans_canonical_equiv]; refl
lemma
class_group.mk_canonical_equiv
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "algebra", "class_group.mk", "field", "fractional_ideal", "fractional_ideal.canonical_equiv_trans_canonical_equiv", "is_fraction_ring", "monoid_hom.comp_apply", "ring_equiv.coe_monoid_hom_trans", "units.map", "units.map_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fractional_ideal.mk0 [is_dedekind_domain R] : (ideal R)⁰ →* (fractional_ideal R⁰ K)ˣ
{ to_fun := λ I, units.mk0 I (coe_ideal_ne_zero.mpr $ mem_non_zero_divisors_iff_ne_zero.mp I.2), map_one' := by simp, map_mul' := λ x y, by simp }
def
fractional_ideal.mk0
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "fractional_ideal", "ideal", "is_dedekind_domain", "units.mk0" ]
Send a nonzero integral ideal to an invertible fractional ideal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fractional_ideal.coe_mk0 [is_dedekind_domain R] (I : (ideal R)⁰) : (fractional_ideal.mk0 K I : fractional_ideal R⁰ K) = I
rfl
lemma
fractional_ideal.coe_mk0
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "fractional_ideal", "fractional_ideal.mk0", "ideal", "is_dedekind_domain" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fractional_ideal.canonical_equiv_mk0 [is_dedekind_domain R] (K' : Type*) [field K'] [algebra R K'] [is_fraction_ring R K'] (I : (ideal R)⁰) : fractional_ideal.canonical_equiv R⁰ K K' (fractional_ideal.mk0 K I) = fractional_ideal.mk0 K' I
by simp only [fractional_ideal.coe_mk0, coe_coe, fractional_ideal.canonical_equiv_coe_ideal]
lemma
fractional_ideal.canonical_equiv_mk0
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "algebra", "coe_coe", "field", "fractional_ideal.canonical_equiv", "fractional_ideal.canonical_equiv_coe_ideal", "fractional_ideal.coe_mk0", "fractional_ideal.mk0", "ideal", "is_dedekind_domain", "is_fraction_ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fractional_ideal.map_canonical_equiv_mk0 [is_dedekind_domain R] (K' : Type*) [field K'] [algebra R K'] [is_fraction_ring R K'] (I : (ideal R)⁰) : units.map ↑(fractional_ideal.canonical_equiv R⁰ K K') (fractional_ideal.mk0 K I) = fractional_ideal.mk0 K' I
units.ext (fractional_ideal.canonical_equiv_mk0 K K' I)
lemma
fractional_ideal.map_canonical_equiv_mk0
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "algebra", "field", "fractional_ideal.canonical_equiv", "fractional_ideal.canonical_equiv_mk0", "fractional_ideal.mk0", "ideal", "is_dedekind_domain", "is_fraction_ring", "units.ext", "units.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk0 [is_dedekind_domain R] : (ideal R)⁰ →* class_group R
class_group.mk.comp (fractional_ideal.mk0 (fraction_ring R))
def
class_group.mk0
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group", "fraction_ring", "fractional_ideal.mk0", "ideal", "is_dedekind_domain" ]
Send a nonzero ideal to the corresponding class in the class group.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk_mk0 [is_dedekind_domain R] (I : (ideal R)⁰): class_group.mk (fractional_ideal.mk0 K I) = class_group.mk0 I
by rw [class_group.mk0, monoid_hom.comp_apply, ← class_group.mk_canonical_equiv K (fraction_ring R), fractional_ideal.map_canonical_equiv_mk0]
lemma
class_group.mk_mk0
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.mk", "class_group.mk0", "class_group.mk_canonical_equiv", "fraction_ring", "fractional_ideal.map_canonical_equiv_mk0", "fractional_ideal.mk0", "ideal", "is_dedekind_domain", "monoid_hom.comp_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.equiv_mk0 [is_dedekind_domain R] (I : (ideal R)⁰): class_group.equiv K (class_group.mk0 I) = quotient_group.mk' (to_principal_ideal R K).range (fractional_ideal.mk0 K I)
begin rw [class_group.mk0, monoid_hom.comp_apply, class_group.equiv_mk], congr, ext, simp end
lemma
class_group.equiv_mk0
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.equiv", "class_group.equiv_mk", "class_group.mk0", "fractional_ideal.mk0", "ideal", "is_dedekind_domain", "monoid_hom.comp_apply", "quotient_group.mk'", "to_principal_ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk0_eq_mk0_iff_exists_fraction_ring [is_dedekind_domain R] {I J : (ideal R)⁰} : class_group.mk0 I = class_group.mk0 J ↔ ∃ (x ≠ (0 : K)), span_singleton R⁰ x * I = J
begin refine (class_group.equiv K).injective.eq_iff.symm.trans _, simp only [class_group.equiv_mk0, quotient_group.mk'_eq_mk', mem_principal_ideals_iff, coe_coe, units.ext_iff, units.coe_mul, fractional_ideal.coe_mk0, exists_prop], split, { rintros ⟨X, ⟨x, hX⟩, hx⟩, refine ⟨x, _, _⟩, { rintro rfl, s...
lemma
class_group.mk0_eq_mk0_iff_exists_fraction_ring
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.equiv", "class_group.equiv_mk0", "class_group.mk0", "coe_coe", "exists_prop", "fractional_ideal.coe_mk0", "ideal", "is_dedekind_domain", "mem_principal_ideals_iff", "mul_comm", "quotient_group.mk'_eq_mk'", "units.coe_mul", "units.ext_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk0_eq_mk0_iff [is_dedekind_domain R] {I J : (ideal R)⁰} : class_group.mk0 I = class_group.mk0 J ↔ ∃ (x y : R) (hx : x ≠ 0) (hy : y ≠ 0), ideal.span {x} * (I : ideal R) = ideal.span {y} * J
begin refine (class_group.mk0_eq_mk0_iff_exists_fraction_ring (fraction_ring R)).trans ⟨_, _⟩, { rintros ⟨z, hz, h⟩, obtain ⟨x, ⟨y, hy⟩, rfl⟩ := is_localization.mk'_surjective R⁰ z, refine ⟨x, y, _, mem_non_zero_divisors_iff_ne_zero.mp hy, _⟩, { rintro hx, apply hz, rw [hx, is_fraction_ring.mk'_eq...
lemma
class_group.mk0_eq_mk0_iff
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "algebra_map", "class_group.mk0", "class_group.mk0_eq_mk0_iff_exists_fraction_ring", "fraction_ring", "fractional_ideal.mk'_mul_coe_ideal_eq_coe_ideal", "ideal", "ideal.span", "is_dedekind_domain", "is_fraction_ring.injective", "is_fraction_ring.mk'_eq_div", "is_localization.mk'_surjective", "...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk0_surjective [is_dedekind_domain R] : function.surjective (class_group.mk0 : (ideal R)⁰ → class_group R)
begin rintros ⟨I⟩, obtain ⟨a, a_ne_zero', ha⟩ := I.1.2, have a_ne_zero := mem_non_zero_divisors_iff_ne_zero.mp a_ne_zero', have fa_ne_zero : (algebra_map R (fraction_ring R)) a ≠ 0 := is_fraction_ring.to_map_ne_zero_of_mem_non_zero_divisors a_ne_zero', refine ⟨⟨{ carrier := { x | (algebra_map R _ a)⁻¹ * a...
lemma
class_group.mk0_surjective
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "algebra.smul_def", "algebra_map", "class_group", "class_group.mk0", "coe_coe", "coe_to_principal_ideal", "fraction_ring", "fractional_ideal", "fractional_ideal.coe_mk0", "fractional_ideal.eq_span_singleton_mul", "fractional_ideal.map_canonical_equiv_mk0", "ideal", "inv_mul_cancel", "is_de...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk_eq_one_iff {I : (fractional_ideal R⁰ K)ˣ} : class_group.mk I = 1 ↔ (I : submodule R K).is_principal
begin simp only [← (class_group.equiv K).injective.eq_iff, _root_.map_one, class_group.equiv_mk, quotient_group.mk'_apply, quotient_group.eq_one_iff, monoid_hom.mem_range, units.ext_iff, coe_to_principal_ideal, units.coe_map_equiv, fractional_ideal.canonical_equiv_self, coe_coe, ring_equiv.coe_mul_e...
lemma
class_group.mk_eq_one_iff
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.equiv", "class_group.equiv_mk", "class_group.mk", "coe_coe", "coe_to_principal_ideal", "fractional_ideal", "fractional_ideal.canonical_equiv_self", "monoid_hom.mem_range", "mul_equiv.refl_apply", "quotient_group.eq_one_iff", "quotient_group.mk'_apply", "ring_equiv.coe_mul_equiv_re...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
class_group.mk0_eq_one_iff [is_dedekind_domain R] {I : ideal R} (hI : I ∈ (ideal R)⁰) : class_group.mk0 ⟨I, hI⟩ = 1 ↔ I.is_principal
class_group.mk_eq_one_iff.trans (coe_submodule_is_principal R _)
lemma
class_group.mk0_eq_one_iff
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group.mk0", "ideal", "is_dedekind_domain" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_class_group_eq_one [is_principal_ideal_ring R] : fintype.card (class_group R) = 1
begin rw fintype.card_eq_one_iff, use 1, refine class_group.induction (fraction_ring R) (λ I, _), exact class_group.mk_eq_one_iff.mpr (I : fractional_ideal R⁰ (fraction_ring R)).is_principal end
lemma
card_class_group_eq_one
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "class_group", "class_group.induction", "fintype.card", "fintype.card_eq_one_iff", "fraction_ring", "fractional_ideal", "is_principal_ideal_ring" ]
The class number of a principal ideal domain is `1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
card_class_group_eq_one_iff [is_dedekind_domain R] [fintype (class_group R)] : fintype.card (class_group R) = 1 ↔ is_principal_ideal_ring R
begin split, swap, { introsI, convert card_class_group_eq_one, assumption, }, rw fintype.card_eq_one_iff, rintros ⟨I, hI⟩, have eq_one : ∀ J : class_group R, J = 1 := λ J, trans (hI J) (hI 1).symm, refine ⟨λ I, _⟩, by_cases hI : I = ⊥, { rw hI, exact bot_is_principal }, exact (class_group.mk0_eq_one_iff...
lemma
card_class_group_eq_one_iff
ring_theory
src/ring_theory/class_group.lean
[ "group_theory.quotient_group", "ring_theory.dedekind_domain.ideal" ]
[ "bot_is_principal", "card_class_group_eq_one", "class_group", "class_group.mk0_eq_one_iff", "fintype", "fintype.card", "fintype.card_eq_one_iff", "is_dedekind_domain", "is_principal_ideal_ring" ]
The class number is `1` iff the ring of integers is a principal ideal domain.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.left_mul_matrix_complex (z : ℂ) : algebra.left_mul_matrix complex.basis_one_I z = !![z.re, -z.im; z.im, z.re]
begin ext i j, rw [algebra.left_mul_matrix_eq_repr_mul, complex.coe_basis_one_I_repr, complex.coe_basis_one_I, mul_re, mul_im, matrix.of_apply], fin_cases j, { simp_rw [matrix.cons_val_zero, one_re, one_im, mul_zero, mul_one, sub_zero, zero_add], fin_cases i; refl }, { simp_rw [matrix.cons_val_one, ma...
lemma
algebra.left_mul_matrix_complex
ring_theory
src/ring_theory/complex.lean
[ "data.complex.module", "ring_theory.norm", "ring_theory.trace" ]
[ "algebra.left_mul_matrix", "algebra.left_mul_matrix_eq_repr_mul", "complex.basis_one_I", "complex.coe_basis_one_I", "complex.coe_basis_one_I_repr", "matrix.cons_val_one", "matrix.cons_val_zero", "matrix.head_cons", "matrix.of_apply", "mul_one", "mul_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.trace_complex_apply (z : ℂ) : algebra.trace ℝ ℂ z = 2*z.re
begin rw [algebra.trace_eq_matrix_trace complex.basis_one_I, algebra.left_mul_matrix_complex, matrix.trace_fin_two], exact (two_mul _).symm end
lemma
algebra.trace_complex_apply
ring_theory
src/ring_theory/complex.lean
[ "data.complex.module", "ring_theory.norm", "ring_theory.trace" ]
[ "algebra.left_mul_matrix_complex", "algebra.trace", "algebra.trace_eq_matrix_trace", "complex.basis_one_I", "matrix.trace_fin_two", "two_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.norm_complex_apply (z : ℂ) : algebra.norm ℝ z = z.norm_sq
begin rw [algebra.norm_eq_matrix_det complex.basis_one_I, algebra.left_mul_matrix_complex, matrix.det_fin_two, norm_sq_apply], simp, end
lemma
algebra.norm_complex_apply
ring_theory
src/ring_theory/complex.lean
[ "data.complex.module", "ring_theory.norm", "ring_theory.trace" ]
[ "algebra.left_mul_matrix_complex", "algebra.norm", "algebra.norm_eq_matrix_det", "complex.basis_one_I", "matrix.det_fin_two" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra.norm_complex_eq : algebra.norm ℝ = norm_sq.to_monoid_hom
monoid_hom.ext algebra.norm_complex_apply
lemma
algebra.norm_complex_eq
ring_theory
src/ring_theory/complex.lean
[ "data.complex.module", "ring_theory.norm", "ring_theory.trace" ]
[ "algebra.norm", "algebra.norm_complex_apply", "monoid_hom.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_con (R : Type*) [has_add R] [has_mul R] extends setoid R
(add' : ∀ {w x y z}, r w x → r y z → r (w + y) (x + z)) (mul' : ∀ {w x y z}, r w x → r y z → r (w * y) (x * z))
structure
ring_con
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_con_gen.rel [has_add R] [has_mul R] (r : R → R → Prop) : R → R → Prop | of : Π x y, r x y → ring_con_gen.rel x y | refl : Π x, ring_con_gen.rel x x | symm : Π {x y}, ring_con_gen.rel x y → ring_con_gen.rel y x | trans : Π {x y z}, ring_con_gen.rel x y → ring_con_gen.rel y z → ring_con_gen.rel x z | add : Π {w x y ...
inductive
ring_con_gen.rel
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
The inductively defined smallest ring congruence relation containing a given binary relation.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_con_gen [has_add R] [has_mul R] (r : R → R → Prop) : ring_con R
{ r := ring_con_gen.rel r, iseqv := ⟨ring_con_gen.rel.refl, @ring_con_gen.rel.symm _ _ _ _, @ring_con_gen.rel.trans _ _ _ _⟩, add' := λ _ _ _ _, ring_con_gen.rel.add, mul' := λ _ _ _ _, ring_con_gen.rel.mul }
def
ring_con_gen
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "ring_con", "ring_con_gen.rel" ]
The inductively defined smallest ring congruence relation containing a given binary relation.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_add_con : add_con R
{ ..c }
def
ring_con.to_add_con
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "add_con" ]
Every `ring_con` is also an `add_con`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_con : con R
{ ..c }
def
ring_con.to_con
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "con" ]
Every `ring_con` is also a `con`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel_eq_coe : c.r = c
rfl
lemma
ring_con.rel_eq_coe
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
refl (x) : c x x
c.refl' x
lemma
ring_con.refl
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
symm {x y} : c x y → c y x
c.symm'
lemma
ring_con.symm
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trans {x y z} : c x y → c y z → c x z
c.trans'
lemma
ring_con.trans
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add {w x y z} : c w x → c y z → c (w + y) (x + z)
c.add'
lemma
ring_con.add
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul {w x y z} : c w x → c y z → c (w * y) (x * z)
c.mul'
lemma
ring_con.mul
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rel_mk {s : setoid R} {ha hm a b} : ring_con.mk s ha hm a b ↔ setoid.r a b
iff.rfl
lemma
ring_con.rel_mk
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient
quotient c.to_setoid
def
ring_con.quotient
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
Defining the quotient by a congruence relation of a type with addition and multiplication.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quot_mk_eq_coe (x : R) : quot.mk c x = (x : c.quotient)
rfl
lemma
ring_con.quot_mk_eq_coe
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq {a b : R} : (a : c.quotient) = b ↔ c a b
quotient.eq'
lemma
ring_con.eq
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "quotient.eq'" ]
Two elements are related by a congruence relation `c` iff they are represented by the same element of the quotient by `c`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_add (x y : R) : (↑(x + y) : c.quotient) = ↑x + ↑y
rfl
lemma
ring_con.coe_add
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_mul (x y : R) : (↑(x * y) : c.quotient) = ↑x * ↑y
rfl
lemma
ring_con.coe_mul
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_zero : (↑(0 : R) : c.quotient) = 0
rfl
lemma
ring_con.coe_zero
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_one : (↑(1 : R) : c.quotient) = 1
rfl
lemma
ring_con.coe_one
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_smul (a : α) (x : R) : (↑(a • x) : c.quotient) = a • x
rfl
lemma
ring_con.coe_smul
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_neg (x : R) : (↑(-x) : c.quotient) = -x
rfl
lemma
ring_con.coe_neg
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_sub (x y : R) : (↑(x - y) : c.quotient) = x - y
rfl
lemma
ring_con.coe_sub
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_zsmul : has_smul ℤ c.quotient
c.to_add_con^.quotient.has_zsmul
instance
ring_con.has_zsmul
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "has_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_zsmul (z : ℤ) (x : R) : (↑(z • x) : c.quotient) = z • x
rfl
lemma
ring_con.coe_zsmul
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_nsmul : has_smul ℕ c.quotient
c.to_add_con^.quotient.has_nsmul
instance
ring_con.has_nsmul
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "has_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_nsmul (n : ℕ) (x : R) : (↑(n • x) : c.quotient) = n • x
rfl
lemma
ring_con.coe_nsmul
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_pow (x : R) (n : ℕ) : (↑(x ^ n) : c.quotient) = x ^ n
rfl
lemma
ring_con.coe_pow
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_nat_cast (n : ℕ) : (↑(n : R) : c.quotient) = n
rfl
lemma
ring_con.coe_nat_cast
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_int_cast (n : ℕ) : (↑(n : R) : c.quotient) = n
rfl
lemma
ring_con.coe_int_cast
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_scalar_tower_right [has_add R] [mul_one_class R] [has_smul α R] [is_scalar_tower α R R] (c : ring_con R) : is_scalar_tower α c.quotient c.quotient
{ smul_assoc := λ a, quotient.ind₂' $ by exact λ m₁ m₂, congr_arg quotient.mk' $ smul_mul_assoc _ _ _ }
instance
ring_con.is_scalar_tower_right
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "has_smul", "is_scalar_tower", "mul_one_class", "quotient.ind₂'", "quotient.mk'", "ring_con", "smul_assoc", "smul_mul_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_comm_class [has_add R] [mul_one_class R] [has_smul α R] [is_scalar_tower α R R] [smul_comm_class α R R] (c : ring_con R) : smul_comm_class α c.quotient c.quotient
{ smul_comm := λ a, quotient.ind₂' $ by exact λ m₁ m₂, congr_arg quotient.mk' $ (mul_smul_comm _ _ _).symm }
instance
ring_con.smul_comm_class
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "has_smul", "is_scalar_tower", "mul_one_class", "mul_smul_comm", "quotient.ind₂'", "quotient.mk'", "ring_con", "smul_comm_class" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_comm_class' [has_add R] [mul_one_class R] [has_smul α R] [is_scalar_tower α R R] [smul_comm_class R α R] (c : ring_con R) : smul_comm_class c.quotient α c.quotient
by haveI := smul_comm_class.symm R α R; exact smul_comm_class.symm _ _ _
instance
ring_con.smul_comm_class'
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "has_smul", "is_scalar_tower", "mul_one_class", "ring_con", "smul_comm_class", "smul_comm_class.symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk' [non_assoc_semiring R] (c : ring_con R) : R →+* c.quotient
{ to_fun := quotient.mk', map_zero' := rfl, map_one' := rfl, map_add' := λ _ _, rfl, map_mul' := λ _ _, rfl }
def
ring_con.mk'
ring_theory
src/ring_theory/congruence.lean
[ "algebra.group_ring_action.basic", "algebra.hom.ring", "algebra.ring.inj_surj", "group_theory.congruence" ]
[ "mk'", "non_assoc_semiring", "quotient.mk'", "ring_con" ]
The natural homomorphism from a ring to its quotient by a congruence relation.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr (A : Type u) {B : Type v} [comm_ring A] [comm_ring B] [algebra A B] [fintype ι] (b : ι → B)
by { classical, exact (trace_matrix A b).det }
def
algebra.discr
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra", "comm_ring", "fintype" ]
Given an `A`-algebra `B` and `b`, an `ι`-indexed family of elements of `B`, we define `discr A ι b` as the determinant of `trace_matrix A ι b`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_def [decidable_eq ι] [fintype ι] (b : ι → B) : discr A b = (trace_matrix A b).det
by convert rfl
lemma
algebra.discr_def
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_reindex (b : basis ι A B) (f : ι ≃ ι') : discr A (b ∘ ⇑(f.symm)) = discr A b
begin classical, rw [← basis.coe_reindex, discr_def, trace_matrix_reindex, det_reindex_self, ← discr_def] end
lemma
algebra.discr_reindex
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "basis", "basis.coe_reindex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_zero_of_not_linear_independent [is_domain A] {b : ι → B} (hli : ¬linear_independent A b) : discr A b = 0
begin classical, obtain ⟨g, hg, i, hi⟩ := fintype.not_linear_independent_iff.1 hli, have : (trace_matrix A b).mul_vec g = 0, { ext i, have : ∀ j, (trace A B) (b i * b j) * g j = (trace A B) (((g j) • (b j)) * b i), { intro j, simp [mul_comm], }, simp only [mul_vec, dot_product, trace_matrix_apply, p...
lemma
algebra.discr_zero_of_not_linear_independent
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "by_contra", "is_domain", "linear_independent", "linear_map.map_sum", "linear_map.map_zero", "matrix.eq_zero_of_mul_vec_eq_zero", "mul_comm", "zero_mul" ]
If `b` is not linear independent, then `algebra.discr A b = 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_of_matrix_vec_mul [decidable_eq ι] (b : ι → B) (P : matrix ι ι A) : discr A ((P.map (algebra_map A B)).vec_mul b) = P.det ^ 2 * discr A b
by rw [discr_def, trace_matrix_of_matrix_vec_mul, det_mul, det_mul, det_transpose, mul_comm, ← mul_assoc, discr_def, pow_two]
lemma
algebra.discr_of_matrix_vec_mul
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra_map", "matrix", "mul_assoc", "mul_comm", "pow_two" ]
Relation between `algebra.discr A ι b` and `algebra.discr A ((P.map (algebra_map A B)).vec_mul b)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_of_matrix_mul_vec [decidable_eq ι] (b : ι → B) (P : matrix ι ι A) : discr A ((P.map (algebra_map A B)).mul_vec b) = P.det ^ 2 * discr A b
by rw [discr_def, trace_matrix_of_matrix_mul_vec, det_mul, det_mul, det_transpose, mul_comm, ← mul_assoc, discr_def, pow_two]
lemma
algebra.discr_of_matrix_mul_vec
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra_map", "matrix", "mul_assoc", "mul_comm", "pow_two" ]
Relation between `algebra.discr A ι b` and `algebra.discr A ((P.map (algebra_map A B)).mul_vec b)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_not_zero_of_basis [is_separable K L] (b : basis ι K L) : discr K b ≠ 0
begin casesI is_empty_or_nonempty ι, { simp [discr] }, { have := span_eq_top_of_linear_independent_of_card_eq_finrank b.linear_independent (finrank_eq_card_basis b).symm, classical, rw [discr_def, trace_matrix], simp_rw [← basis.mk_apply b.linear_independent this.ge], rw [← trace_matrix, tra...
lemma
algebra.discr_not_zero_of_basis
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "basis", "basis.mk_apply", "bilin_form.nondegenerate_iff_det_ne_zero", "is_empty_or_nonempty", "is_separable", "span_eq_top_of_linear_independent_of_card_eq_finrank", "trace_form_nondegenerate" ]
Over a field, if `b` is a basis, then `algebra.discr K b ≠ 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_is_unit_of_basis [is_separable K L] (b : basis ι K L) : is_unit (discr K b)
is_unit.mk0 _ (discr_not_zero_of_basis _ _)
lemma
algebra.discr_is_unit_of_basis
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "basis", "is_separable", "is_unit", "is_unit.mk0" ]
Over a field, if `b` is a basis, then `algebra.discr K b` is a unit.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_eq_det_embeddings_matrix_reindex_pow_two [decidable_eq ι] [is_separable K L] (e : ι ≃ (L →ₐ[K] E)) : algebra_map K E (discr K b) = (embeddings_matrix_reindex K E b e).det ^ 2
by rw [discr_def, ring_hom.map_det, ring_hom.map_matrix_apply, trace_matrix_eq_embeddings_matrix_reindex_mul_trans, det_mul, det_transpose, pow_two]
lemma
algebra.discr_eq_det_embeddings_matrix_reindex_pow_two
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra_map", "is_separable", "pow_two", "ring_hom.map_det" ]
If `L/K` is a field extension and `b : ι → L`, then `discr K b` is the square of the determinant of the matrix whose `(i, j)` coefficient is `σⱼ (b i)`, where `σⱼ : L →ₐ[K] E` is the embedding in an algebraically closed field `E` corresponding to `j : ι` via a bijection `e : ι ≃ (L →ₐ[K] E)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_power_basis_eq_prod (e : fin pb.dim ≃ (L →ₐ[K] E)) [is_separable K L] : algebra_map K E (discr K pb.basis) = ∏ i : fin pb.dim, ∏ j in Ioi i, (e j pb.gen- (e i pb.gen)) ^ 2
begin rw [discr_eq_det_embeddings_matrix_reindex_pow_two K E pb.basis e, embeddings_matrix_reindex_eq_vandermonde, det_transpose, det_vandermonde, ← prod_pow], congr, ext i, rw [← prod_pow] end
lemma
algebra.discr_power_basis_eq_prod
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra_map", "is_separable" ]
The discriminant of a power basis.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_power_basis_eq_prod' [is_separable K L] (e : fin pb.dim ≃ (L →ₐ[K] E)) : algebra_map K E (discr K pb.basis) = ∏ i : fin pb.dim, ∏ j in Ioi i, -((e j pb.gen - e i pb.gen) * (e i pb.gen - e j pb.gen))
begin rw [discr_power_basis_eq_prod _ _ _ e], congr, ext i, congr, ext j, ring end
lemma
algebra.discr_power_basis_eq_prod'
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra_map", "is_separable", "ring" ]
A variation of `of_power_basis_eq_prod`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_power_basis_eq_prod'' [is_separable K L] (e : fin pb.dim ≃ (L →ₐ[K] E)) : algebra_map K E (discr K pb.basis) = (-1) ^ (n * (n - 1) / 2) * ∏ i : fin pb.dim, ∏ j in Ioi i, (e j pb.gen - e i pb.gen) * (e i pb.gen - e j pb.gen)
begin rw [discr_power_basis_eq_prod' _ _ _ e], simp_rw [λ i j, neg_eq_neg_one_mul ((e j pb.gen- (e i pb.gen)) * (e i pb.gen- (e j pb.gen))), prod_mul_distrib], congr, simp only [prod_pow_eq_pow_sum, prod_const], congr, rw [← @nat.cast_inj ℚ, nat.cast_sum], have : ∀ (x : fin pb.dim), (↑x + 1) ≤ pb.dim ...
lemma
algebra.discr_power_basis_eq_prod''
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "alg_hom.card", "algebra_map", "equiv.symm", "fin.card_Ioi", "fin.is_lt", "finite_dimensional.finrank_pos_iff", "finset.card_fin", "fintype.card_fin", "is_separable", "mul_one", "nat.cast_add", "nat.cast_div", "nat.cast_inj", "nat.cast_mul", "nat.cast_one", "nat.cast_sub", "nat.cast_...
A variation of `of_power_basis_eq_prod`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_power_basis_eq_norm [is_separable K L] : discr K pb.basis = (-1) ^ (n * (n - 1) / 2) * (norm K (aeval pb.gen (minpoly K pb.gen).derivative))
begin let E := algebraic_closure L, letI := λ (a b : E), classical.prop_decidable (eq a b), have e : fin pb.dim ≃ (L →ₐ[K] E), { refine equiv_of_card_eq _, rw [fintype.card_fin, alg_hom.card], exact (power_basis.finrank pb).symm }, have hnodup : (map (algebra_map K E) (minpoly K pb.gen)).roots.nodup ...
lemma
algebra.discr_power_basis_eq_norm
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "alg_hom.card", "alg_hom.congr_fun", "algebra_map", "algebraic_closure", "equiv.apply_eq_iff_eq", "equiv.injective", "exists_prop", "finset.mem_mk", "finset.prod_mk", "fintype.card_fin", "heq_iff_eq", "is_alg_closed.splits_codomain", "is_separable", "is_separable.is_integral", "is_separa...
Formula for the discriminant of a power basis using the norm of the field extension.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_is_integral {b : ι → L} (h : ∀ i, is_integral R (b i)) : is_integral R (discr K b)
begin classical, rw [discr_def], exact is_integral.det (λ i j, is_integral_trace (is_integral_mul (h i) (h j))) end
lemma
algebra.discr_is_integral
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "is_integral", "is_integral.det", "is_integral_mul" ]
If `K` and `L` are fields and `is_scalar_tower R K L`, and `b : ι → L` satisfies ` ∀ i, is_integral R (b i)`, then `is_integral R (discr K b)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_eq_discr_of_to_matrix_coeff_is_integral [number_field K] {b : basis ι ℚ K} {b' : basis ι' ℚ K} (h : ∀ i j, is_integral ℤ (b.to_matrix b' i j)) (h' : ∀ i j, is_integral ℤ (b'.to_matrix b i j)) : discr ℚ b = discr ℚ b'
begin replace h' : ∀ i j, is_integral ℤ (b'.to_matrix ((b.reindex (b.index_equiv b'))) i j), { intros i j, convert h' i ((b.index_equiv b').symm j), simpa }, classical, rw [← (b.reindex (b.index_equiv b')).to_matrix_map_vec_mul b', discr_of_matrix_vec_mul, ← one_mul (discr ℚ b), basis.coe_reindex, d...
lemma
algebra.discr_eq_discr_of_to_matrix_coeff_is_integral
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra_map", "basis", "basis.coe_reindex", "basis.to_matrix_mul_to_matrix_flip", "is_fraction_ring.injective", "is_integral", "is_integral.det", "is_unit", "number_field", "one_mul", "ring_hom.map_mul", "ring_hom.map_one" ]
If `b` and `b'` are `ℚ`-bases of a number field `K` such that `∀ i j, is_integral ℤ (b.to_matrix b' i j)` and `∀ i j, is_integral ℤ (b'.to_matrix b i j)` then `discr ℚ b = discr ℚ b'`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discr_mul_is_integral_mem_adjoin [is_domain R] [is_separable K L] [is_integrally_closed R] [is_fraction_ring R K] {B : power_basis K L} (hint : is_integral R B.gen) {z : L} (hz : is_integral R z) : (discr K B.basis) • z ∈ adjoin R ({B.gen} : set L)
begin have hinv : is_unit (trace_matrix K B.basis).det := by simpa [← discr_def] using discr_is_unit_of_basis _ B.basis, have H : (trace_matrix K B.basis).det • (trace_matrix K B.basis).mul_vec (B.basis.equiv_fun z) = (trace_matrix K B.basis).det • (λ i, trace K L (z * B.basis i)), { congr, exact trace_m...
lemma
algebra.discr_mul_is_integral_mem_adjoin
ring_theory
src/ring_theory/discriminant.lean
[ "ring_theory.trace", "ring_theory.norm", "number_theory.number_field.basic" ]
[ "algebra_map_smul", "basis.equiv_fun_apply", "finset.smul_sum", "is_domain", "is_fraction_ring", "is_integral", "is_integral.pow", "is_integral_mul", "is_integrally_closed", "is_separable", "is_unit", "pi.smul_apply", "power_basis", "power_basis.coe_basis", "set.mem_singleton", "smul_a...
Let `K` be the fraction field of an integrally closed domain `R` and let `L` be a finite separable extension of `K`. Let `B : power_basis K L` be such that `is_integral R B.gen`. Then for all, `z : L` that are integral over `R`, we have `(discr K B.basis) • z ∈ adjoin R ({B.gen} : set L)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_eq_C_mul_X_pow_of_forall_coeff_mem {f : R[X]} {P : ideal R} (hfP : ∀ (n : ℕ), ↑n < f.degree → f.coeff n ∈ P) : map (mk P) f = C ((mk P) f.leading_coeff) * X ^ f.nat_degree
polynomial.ext (λ n, begin by_cases hf0 : f = 0, { simp [hf0], }, rcases lt_trichotomy ↑n (degree f) with h | h | h, { erw [coeff_map, eq_zero_iff_mem.2 (hfP n h), coeff_C_mul, coeff_X_pow, if_neg, mul_zero], rintro rfl, exact not_lt_of_ge degree_le_nat_degree h }, { have : nat_degree f = n, from nat_degree...
lemma
polynomial.eisenstein_criterion_aux.map_eq_C_mul_X_pow_of_forall_coeff_mem
ring_theory
src/ring_theory/eisenstein_criterion.lean
[ "data.nat.cast.with_top", "ring_theory.prime", "ring_theory.polynomial.content", "ring_theory.ideal.quotient_operations" ]
[ "ideal", "mul_one", "mul_zero", "polynomial.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_nat_degree_of_map_eq_mul_X_pow {n : ℕ} {P : ideal R} (hP : P.is_prime) {q : R[X]} {c : polynomial (R ⧸ P)} (hq : map (mk P) q = c * X ^ n) (hc0 : c.degree = 0) : n ≤ q.nat_degree
with_bot.coe_le_coe.1 (calc ↑n = degree (q.map (mk P)) : by rw [hq, degree_mul, hc0, zero_add, degree_pow, degree_X, nsmul_one, nat.cast_with_bot] ... ≤ degree q : degree_map_le _ _ ... ≤ nat_degree q : degree_le_nat_degree)
lemma
polynomial.eisenstein_criterion_aux.le_nat_degree_of_map_eq_mul_X_pow
ring_theory
src/ring_theory/eisenstein_criterion.lean
[ "data.nat.cast.with_top", "ring_theory.prime", "ring_theory.polynomial.content", "ring_theory.ideal.quotient_operations" ]
[ "ideal", "nat.cast_with_bot", "nsmul_one", "polynomial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval_zero_mem_ideal_of_eq_mul_X_pow {n : ℕ} {P : ideal R} {q : R[X]} {c : polynomial (R ⧸ P)} (hq : map (mk P) q = c * X ^ n) (hn0 : 0 < n) : eval 0 q ∈ P
by rw [← coeff_zero_eq_eval_zero, ← eq_zero_iff_mem, ← coeff_map, coeff_zero_eq_eval_zero, hq, eval_mul, eval_pow, eval_X, zero_pow hn0, mul_zero]
lemma
polynomial.eisenstein_criterion_aux.eval_zero_mem_ideal_of_eq_mul_X_pow
ring_theory
src/ring_theory/eisenstein_criterion.lean
[ "data.nat.cast.with_top", "ring_theory.prime", "ring_theory.polynomial.content", "ring_theory.ideal.quotient_operations" ]
[ "ideal", "mul_zero", "polynomial", "zero_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_of_nat_degree_eq_zero_of_forall_dvd_is_unit {p q : R[X]} (hu : ∀ (x : R), C x ∣ p * q → is_unit x) (hpm : p.nat_degree = 0) : is_unit p
begin rw [eq_C_of_degree_le_zero (nat_degree_eq_zero_iff_degree_le_zero.1 hpm), is_unit_C], refine hu _ _, rw [← eq_C_of_degree_le_zero (nat_degree_eq_zero_iff_degree_le_zero.1 hpm)], exact dvd_mul_right _ _ end
lemma
polynomial.eisenstein_criterion_aux.is_unit_of_nat_degree_eq_zero_of_forall_dvd_is_unit
ring_theory
src/ring_theory/eisenstein_criterion.lean
[ "data.nat.cast.with_top", "ring_theory.prime", "ring_theory.polynomial.content", "ring_theory.ideal.quotient_operations" ]
[ "dvd_mul_right", "is_unit" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
irreducible_of_eisenstein_criterion {f : R[X]} {P : ideal R} (hP : P.is_prime) (hfl : f.leading_coeff ∉ P) (hfP : ∀ n : ℕ, ↑n < degree f → f.coeff n ∈ P) (hfd0 : 0 < degree f) (h0 : f.coeff 0 ∉ P^2) (hu : f.is_primitive) : irreducible f
have hf0 : f ≠ 0, from λ _, by simp only [*, not_true, submodule.zero_mem, coeff_zero] at *, have hf : f.map (mk P) = C (mk P (leading_coeff f)) * X ^ nat_degree f, from map_eq_C_mul_X_pow_of_forall_coeff_mem hfP, have hfd0 : 0 < f.nat_degree, from with_bot.coe_lt_coe.1 (lt_of_lt_of_le hfd0 degree_le_nat_degree), ⟨...
theorem
polynomial.irreducible_of_eisenstein_criterion
ring_theory
src/ring_theory/eisenstein_criterion.lean
[ "data.nat.cast.with_top", "ring_theory.prime", "ring_theory.polynomial.content", "ring_theory.ideal.quotient_operations" ]
[ "ideal", "ideal.mul_mem_mul", "imp_false", "irreducible", "mul_comm", "mul_eq_mul_prime_pow", "mul_zero", "nat.with_bot.add_eq_zero_iff", "not_and_distrib", "not_not", "or_iff_not_imp_left", "polynomial", "polynomial.map_mul", "prime", "submodule.zero_mem", "zero_mul" ]
If `f` is a non constant polynomial with coefficients in `R`, and `P` is a prime ideal in `R`, then if every coefficient in `R` except the leading coefficient is in `P`, and the trailing coefficient is not in `P^2` and no non units in `R` divide `f`, then `f` is irreducible.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_unramified : Prop
(comp_injective : ∀ ⦃B : Type u⦄ [comm_ring B], by exactI ∀ [algebra R B] (I : ideal B) (hI : I ^ 2 = ⊥), by exactI function.injective ((ideal.quotient.mkₐ R I).comp : (A →ₐ[R] B) → (A →ₐ[R] B ⧸ I)))
class
algebra.formally_unramified
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[ "algebra", "comm_ring", "ideal", "ideal.quotient.mkₐ" ]
An `R`-algebra `A` is formally unramified if for every `R`-algebra, every square-zero ideal `I : ideal B` and `f : A →ₐ[R] B ⧸ I`, there exists at most one lift `A →ₐ[R] B`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_smooth : Prop
(comp_surjective : ∀ ⦃B : Type u⦄ [comm_ring B], by exactI ∀ [algebra R B] (I : ideal B) (hI : I ^ 2 = ⊥), by exactI function.surjective ((ideal.quotient.mkₐ R I).comp : (A →ₐ[R] B) → (A →ₐ[R] B ⧸ I)))
class
algebra.formally_smooth
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[ "algebra", "comm_ring", "ideal", "ideal.quotient.mkₐ" ]
An `R` algebra `A` is formally smooth if for every `R`-algebra, every square-zero ideal `I : ideal B` and `f : A →ₐ[R] B ⧸ I`, there exists at least one lift `A →ₐ[R] B`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_etale : Prop
(comp_bijective : ∀ ⦃B : Type u⦄ [comm_ring B], by exactI ∀ [algebra R B] (I : ideal B) (hI : I ^ 2 = ⊥), by exactI function.bijective ((ideal.quotient.mkₐ R I).comp : (A →ₐ[R] B) → (A →ₐ[R] B ⧸ I)))
class
algebra.formally_etale
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[ "algebra", "comm_ring", "ideal", "ideal.quotient.mkₐ" ]
An `R` algebra `A` is formally étale if for every `R`-algebra, every square-zero ideal `I : ideal B` and `f : A →ₐ[R] B ⧸ I`, there exists exactly one lift `A →ₐ[R] B`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_etale.iff_unramified_and_smooth : formally_etale R A ↔ formally_unramified R A ∧ formally_smooth R A
begin rw [formally_unramified_iff, formally_smooth_iff, formally_etale_iff], simp_rw ← forall_and_distrib, refl end
lemma
algebra.formally_etale.iff_unramified_and_smooth
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[ "forall_and_distrib" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_etale.to_unramified [h : formally_etale R A] : formally_unramified R A
(formally_etale.iff_unramified_and_smooth.mp h).1
instance
algebra.formally_etale.to_unramified
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_etale.to_smooth [h : formally_etale R A] : formally_smooth R A
(formally_etale.iff_unramified_and_smooth.mp h).2
instance
algebra.formally_etale.to_smooth
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_etale.of_unramified_and_smooth [h₁ : formally_unramified R A] [h₂ : formally_smooth R A] : formally_etale R A
formally_etale.iff_unramified_and_smooth.mpr ⟨h₁, h₂⟩
lemma
algebra.formally_etale.of_unramified_and_smooth
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_unramified.lift_unique {B : Type u} [comm_ring B] [_RB : algebra R B] [formally_unramified R A] (I : ideal B) (hI : is_nilpotent I) (g₁ g₂ : A →ₐ[R] B) (h : (ideal.quotient.mkₐ R I).comp g₁ = (ideal.quotient.mkₐ R I).comp g₂) : g₁ = g₂
begin revert g₁ g₂, change function.injective (ideal.quotient.mkₐ R I).comp, unfreezingI { revert _RB }, apply ideal.is_nilpotent.induction_on I hI, { introsI B _ I hI _, exact formally_unramified.comp_injective I hI }, { introsI B _ I J hIJ h₁ h₂ _ g₁ g₂ e, apply h₁, apply h₂, ext x, replac...
lemma
algebra.formally_unramified.lift_unique
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[ "alg_hom.comp_apply", "alg_hom.congr_fun", "algebra", "comm_ring", "ideal", "ideal.is_nilpotent.induction_on", "ideal.mem_quotient_iff_mem", "ideal.quotient.eq", "ideal.quotient.mkₐ", "ideal.quotient.mkₐ_eq_mk", "is_nilpotent" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_unramified.ext [formally_unramified R A] (hI : is_nilpotent I) {g₁ g₂ : A →ₐ[R] B} (H : ∀ x, ideal.quotient.mk I (g₁ x) = ideal.quotient.mk I (g₂ x)) : g₁ = g₂
formally_unramified.lift_unique I hI g₁ g₂ (alg_hom.ext H)
lemma
algebra.formally_unramified.ext
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[ "alg_hom.ext", "ideal.quotient.mk", "is_nilpotent" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
formally_unramified.lift_unique_of_ring_hom [formally_unramified R A] {C : Type u} [comm_ring C] (f : B →+* C) (hf : is_nilpotent f.ker) (g₁ g₂ : A →ₐ[R] B) (h : f.comp ↑g₁ = f.comp (g₂ : A →+* B)) : g₁ = g₂
formally_unramified.lift_unique _ hf _ _ begin ext x, have := ring_hom.congr_fun h x, simpa only [ideal.quotient.eq, function.comp_app, alg_hom.coe_comp, ideal.quotient.mkₐ_eq_mk, ring_hom.mem_ker, map_sub, sub_eq_zero], end
lemma
algebra.formally_unramified.lift_unique_of_ring_hom
ring_theory
src/ring_theory/etale.lean
[ "ring_theory.quotient_nilpotent", "ring_theory.kaehler" ]
[ "alg_hom.coe_comp", "comm_ring", "ideal.quotient.eq", "ideal.quotient.mkₐ_eq_mk", "is_nilpotent", "ring_hom.congr_fun", "ring_hom.mem_ker" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83