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derivation_to_square_zero_equiv_lift : derivation R A I ≃ { f : A →ₐ[R] B // (ideal.quotient.mkₐ R I).comp f = is_scalar_tower.to_alg_hom R A (B ⧸ I) }
begin refine ⟨λ d, ⟨lift_of_derivation_to_square_zero I hI d, _⟩, λ f, (derivation_to_square_zero_of_lift I hI f.1 f.2 : _), _, _⟩, { ext x, exact lift_of_derivation_to_square_zero_mk_apply I hI d x }, { intro d, ext x, exact add_sub_cancel (d x : B) (algebra_map A B x) }, { rintro ⟨f, hf⟩, ext x, exact su...
def
derivation_to_square_zero_equiv_lift
ring_theory.derivation
src/ring_theory/derivation/to_square_zero.lean
[ "ring_theory.derivation.basic", "ring_theory.ideal.quotient_operations" ]
[ "algebra_map", "derivation", "derivation_to_square_zero_of_lift", "ideal.quotient.mkₐ", "is_scalar_tower.to_alg_hom", "lift_of_derivation_to_square_zero_mk_apply" ]
Given a tower of algebras `R → A → B`, and a square-zero `I : ideal B`, there is a 1-1 correspondance between `R`-derivations from `A` to `I` and lifts `A →ₐ[R] B` of the canonical map `A →ₐ[R] B ⧸ I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discrete_valuation_ring (R : Type u) [comm_ring R] [is_domain R] extends is_principal_ideal_ring R, local_ring R : Prop
(not_a_field' : maximal_ideal R ≠ ⊥)
class
discrete_valuation_ring
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "comm_ring", "is_domain", "is_principal_ideal_ring", "local_ring" ]
An integral domain is a *discrete valuation ring* (DVR) if it's a local PID which is not a field.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
not_a_field : maximal_ideal R ≠ ⊥
not_a_field'
lemma
discrete_valuation_ring.not_a_field
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
not_is_field : ¬ is_field R
local_ring.is_field_iff_maximal_ideal_eq.not.mpr (not_a_field R)
lemma
discrete_valuation_ring.not_is_field
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "is_field" ]
A discrete valuation ring `R` is not a field.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
irreducible_of_span_eq_maximal_ideal {R : Type*} [comm_ring R] [local_ring R] [is_domain R] (ϖ : R) (hϖ : ϖ ≠ 0) (h : maximal_ideal R = ideal.span {ϖ}) : irreducible ϖ
begin have h2 : ¬(is_unit ϖ) := show ϖ ∈ maximal_ideal R, from h.symm ▸ submodule.mem_span_singleton_self ϖ, refine ⟨h2, _⟩, intros a b hab, by_contra' h, obtain ⟨ha : a ∈ maximal_ideal R, hb : b ∈ maximal_ideal R⟩ := h, rw [h, mem_span_singleton'] at ha hb, rcases ha with ⟨a, rfl⟩, rcases hb with ⟨...
theorem
discrete_valuation_ring.irreducible_of_span_eq_maximal_ideal
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "comm_ring", "eq_zero_of_mul_eq_self_right", "ideal.span", "irreducible", "is_domain", "is_unit", "is_unit_of_dvd_one", "local_ring", "ring", "submodule.mem_span_singleton_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
irreducible_iff_uniformizer (ϖ : R) : irreducible ϖ ↔ maximal_ideal R = ideal.span {ϖ}
⟨λ hϖ, (eq_maximal_ideal (is_maximal_of_irreducible hϖ)).symm, λ h, irreducible_of_span_eq_maximal_ideal ϖ (λ e, not_a_field R $ by rwa [h, span_singleton_eq_bot]) h⟩
theorem
discrete_valuation_ring.irreducible_iff_uniformizer
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "ideal.span", "irreducible" ]
An element of a DVR is irreducible iff it is a uniformizer, that is, generates the maximal ideal of R
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.irreducible.maximal_ideal_eq {ϖ : R} (h : irreducible ϖ) : maximal_ideal R = ideal.span {ϖ}
(irreducible_iff_uniformizer _).mp h
lemma
irreducible.maximal_ideal_eq
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "ideal.span", "irreducible" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_irreducible : ∃ ϖ : R, irreducible ϖ
by {simp_rw [irreducible_iff_uniformizer], exact (is_principal_ideal_ring.principal $ maximal_ideal R).principal}
theorem
discrete_valuation_ring.exists_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "irreducible" ]
Uniformisers exist in a DVR
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_prime : ∃ ϖ : R, prime ϖ
(exists_irreducible R).imp (λ _, principal_ideal_ring.irreducible_iff_prime.1)
theorem
discrete_valuation_ring.exists_prime
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "prime" ]
Uniformisers exist in a DVR
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iff_pid_with_one_nonzero_prime (R : Type u) [comm_ring R] [is_domain R] : discrete_valuation_ring R ↔ is_principal_ideal_ring R ∧ ∃! P : ideal R, P ≠ ⊥ ∧ is_prime P
begin split, { intro RDVR, rcases id RDVR with ⟨Rlocal⟩, split, assumption, resetI, use local_ring.maximal_ideal R, split, split, { assumption }, { apply_instance } , { rintro Q ⟨hQ1, hQ2⟩, obtain ⟨q, rfl⟩ := (is_principal_ideal_ring.principal Q).1, have hq : q ≠ 0, ...
theorem
discrete_valuation_ring.iff_pid_with_one_nonzero_prime
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "comm_ring", "discrete_valuation_ring", "ideal", "is_domain", "is_principal_ideal_ring", "le_bot_iff", "local_ring", "local_ring.maximal_ideal", "local_ring.of_unique_nonzero_prime" ]
an integral domain is a DVR iff it's a PID with a unique non-zero prime ideal
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
associated_of_irreducible {a b : R} (ha : irreducible a) (hb : irreducible b) : associated a b
begin rw irreducible_iff_uniformizer at ha hb, rw [←span_singleton_eq_span_singleton, ←ha, hb], end
lemma
discrete_valuation_ring.associated_of_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "associated", "irreducible" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_unit_mul_pow_irreducible_factorization [comm_ring R] : Prop
∃ p : R, irreducible p ∧ ∀ {x : R}, x ≠ 0 → ∃ (n : ℕ), associated (p ^ n) x
def
discrete_valuation_ring.has_unit_mul_pow_irreducible_factorization
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "associated", "comm_ring", "irreducible" ]
Alternative characterisation of discrete valuation rings.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_irreducible ⦃p q : R⦄ (hp : irreducible p) (hq : irreducible q) : associated p q
begin rcases hR with ⟨ϖ, hϖ, hR⟩, suffices : ∀ {p : R} (hp : irreducible p), associated p ϖ, { apply associated.trans (this hp) (this hq).symm, }, clear hp hq p q, intros p hp, obtain ⟨n, hn⟩ := hR hp.ne_zero, have : irreducible (ϖ ^ n) := hn.symm.irreducible hp, rcases lt_trichotomy n 1 with (H|rfl|H),...
lemma
discrete_valuation_ring.has_unit_mul_pow_irreducible_factorization.unique_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "associated", "associated.trans", "irreducible", "is_unit_of_mul_is_unit_left", "nat.exists_eq_add_of_lt", "not_irreducible_one", "pow_one", "pow_succ", "pow_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_unique_factorization_monoid : unique_factorization_monoid R
let p := classical.some hR in let spec := classical.some_spec hR in unique_factorization_monoid.of_exists_prime_factors $ λ x hx, begin use multiset.replicate (classical.some (spec.2 hx)) p, split, { intros q hq, have hpq := multiset.eq_of_mem_replicate hq, rw hpq, refine ⟨spec.1.ne_zero, spec.1.not_u...
theorem
discrete_valuation_ring.has_unit_mul_pow_irreducible_factorization.to_unique_factorization_monoid
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "dvd_mul_of_dvd_left", "dvd_rfl", "dvd_zero", "is_unit.dvd_mul_left", "is_unit.dvd_mul_right", "mul_assoc", "mul_left_comm", "multiset.eq_of_mem_replicate", "multiset.prod_replicate", "multiset.replicate", "one_mul", "pow_succ", "pow_zero", "unique_factorization_monoid", "unique_factoriz...
An integral domain in which there is an irreducible element `p` such that every nonzero element is associated to a power of `p` is a unique factorization domain. See `discrete_valuation_ring.of_has_unit_mul_pow_irreducible_factorization`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_ufd_of_unique_irreducible [unique_factorization_monoid R] (h₁ : ∃ p : R, irreducible p) (h₂ : ∀ ⦃p q : R⦄, irreducible p → irreducible q → associated p q) : has_unit_mul_pow_irreducible_factorization R
begin obtain ⟨p, hp⟩ := h₁, refine ⟨p, hp, _⟩, intros x hx, cases wf_dvd_monoid.exists_factors x hx with fx hfx, refine ⟨fx.card, _⟩, have H := hfx.2, rw ← associates.mk_eq_mk_iff_associated at H ⊢, rw [← H, ← associates.prod_mk, associates.mk_pow, ← multiset.prod_replicate], congr' 1, symmetry, r...
lemma
discrete_valuation_ring.has_unit_mul_pow_irreducible_factorization.of_ufd_of_unique_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "and_imp", "associated", "associates.mk_eq_mk_iff_associated", "associates.mk_pow", "associates.prod_mk", "exists_imp_distrib", "irreducible", "multiset.card_map", "multiset.eq_replicate", "multiset.mem_map", "multiset.prod_replicate", "unique_factorization_monoid", "wf_dvd_monoid.exists_fac...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aux_pid_of_ufd_of_unique_irreducible (R : Type u) [comm_ring R] [is_domain R] [unique_factorization_monoid R] (h₁ : ∃ p : R, irreducible p) (h₂ : ∀ ⦃p q : R⦄, irreducible p → irreducible q → associated p q) : is_principal_ideal_ring R
begin constructor, intro I, by_cases I0 : I = ⊥, { rw I0, use 0, simp only [set.singleton_zero, submodule.span_zero], }, obtain ⟨x, hxI, hx0⟩ : ∃ x ∈ I, x ≠ (0:R) := I.ne_bot_iff.mp I0, obtain ⟨p, hp, H⟩ := has_unit_mul_pow_irreducible_factorization.of_ufd_of_unique_irreducible h₁ h₂, have ex : ∃ n : ℕ,...
lemma
discrete_valuation_ring.aux_pid_of_ufd_of_unique_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "associated", "comm_ring", "ideal.span", "irreducible", "is_domain", "is_principal_ideal_ring", "is_unit.dvd_mul_right", "pow_dvd_pow", "submodule.span_singleton_le_iff_mem", "submodule.span_zero", "submodule.zero_mem", "unique_factorization_monoid", "units.is_unit", "units.mul_inv_cancel_...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_ufd_of_unique_irreducible {R : Type u} [comm_ring R] [is_domain R] [unique_factorization_monoid R] (h₁ : ∃ p : R, irreducible p) (h₂ : ∀ ⦃p q : R⦄, irreducible p → irreducible q → associated p q) : discrete_valuation_ring R
begin rw iff_pid_with_one_nonzero_prime, haveI PID : is_principal_ideal_ring R := aux_pid_of_ufd_of_unique_irreducible R h₁ h₂, obtain ⟨p, hp⟩ := h₁, refine ⟨PID, ⟨ideal.span {p}, ⟨_, _⟩, _⟩⟩, { rw submodule.ne_bot_iff, refine ⟨p, ideal.mem_span_singleton.mpr (dvd_refl p), hp.ne_zero⟩, }, { rwa [ideal.s...
lemma
discrete_valuation_ring.of_ufd_of_unique_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "associated", "comm_ring", "discrete_valuation_ring", "dvd_refl", "ideal.span_singleton_prime", "irreducible", "is_domain", "is_principal_ideal_ring", "submodule.is_principal.span_singleton_generator", "submodule.ne_bot_iff", "unique_factorization_monoid" ]
A unique factorization domain with at least one irreducible element in which all irreducible elements are associated is a discrete valuation ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_has_unit_mul_pow_irreducible_factorization {R : Type u} [comm_ring R] [is_domain R] (hR : has_unit_mul_pow_irreducible_factorization R) : discrete_valuation_ring R
begin letI : unique_factorization_monoid R := hR.to_unique_factorization_monoid, apply of_ufd_of_unique_irreducible _ hR.unique_irreducible, unfreezingI { obtain ⟨p, hp, H⟩ := hR, exact ⟨p, hp⟩, }, end
lemma
discrete_valuation_ring.of_has_unit_mul_pow_irreducible_factorization
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "comm_ring", "discrete_valuation_ring", "is_domain", "unique_factorization_monoid" ]
An integral domain in which there is an irreducible element `p` such that every nonzero element is associated to a power of `p` is a discrete valuation ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
associated_pow_irreducible {x : R} (hx : x ≠ 0) {ϖ : R} (hirr : irreducible ϖ) : ∃ (n : ℕ), associated x (ϖ ^ n)
begin have : wf_dvd_monoid R := is_noetherian_ring.wf_dvd_monoid, cases wf_dvd_monoid.exists_factors x hx with fx hfx, unfreezingI { use fx.card }, have H := hfx.2, rw ← associates.mk_eq_mk_iff_associated at H ⊢, rw [← H, ← associates.prod_mk, associates.mk_pow, ← multiset.prod_replicate], congr' 1, rw ...
lemma
discrete_valuation_ring.associated_pow_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "and_imp", "associated", "associates.mk_eq_mk_iff_associated", "associates.mk_pow", "associates.prod_mk", "exists_imp_distrib", "irreducible", "is_noetherian_ring.wf_dvd_monoid", "multiset.card_map", "multiset.eq_replicate", "multiset.mem_map", "multiset.prod_replicate", "wf_dvd_monoid", "...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_unit_mul_pow_irreducible {x : R} (hx : x ≠ 0) {ϖ : R} (hirr : irreducible ϖ) : ∃ (n : ℕ) (u : Rˣ), x = u * ϖ ^ n
begin obtain ⟨n, hn⟩ := associated_pow_irreducible hx hirr, obtain ⟨u, rfl⟩ := hn.symm, use [n, u], apply mul_comm, end
lemma
discrete_valuation_ring.eq_unit_mul_pow_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "irreducible", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal_eq_span_pow_irreducible {s : ideal R} (hs : s ≠ ⊥) {ϖ : R} (hirr : irreducible ϖ) : ∃ n : ℕ, s = ideal.span {ϖ ^ n}
begin have gen_ne_zero : generator s ≠ 0, { rw [ne.def, ← eq_bot_iff_generator_eq_zero], assumption }, rcases associated_pow_irreducible gen_ne_zero hirr with ⟨n, u, hnu⟩, use n, have : span _ = _ := span_singleton_generator s, rw [← this, ← hnu, span_singleton_eq_span_singleton], use u end
lemma
discrete_valuation_ring.ideal_eq_span_pow_irreducible
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "ideal", "ideal.span", "irreducible" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_mul_pow_congr_pow {p q : R} (hp : irreducible p) (hq : irreducible q) (u v : Rˣ) (m n : ℕ) (h : ↑u * p ^ m = v * q ^ n) : m = n
begin have key : associated (multiset.replicate m p).prod (multiset.replicate n q).prod, { rw [multiset.prod_replicate, multiset.prod_replicate, associated], refine ⟨u * v⁻¹, _⟩, simp only [units.coe_mul], rw [mul_left_comm, ← mul_assoc, h, mul_right_comm, units.mul_inv, one_mul], }, have := multiset....
lemma
discrete_valuation_ring.unit_mul_pow_congr_pow
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "associated", "irreducible", "mul_assoc", "mul_left_comm", "mul_right_comm", "multiset.card_eq_card_of_rel", "multiset.card_replicate", "multiset.eq_of_mem_replicate", "multiset.prod_replicate", "multiset.replicate", "one_mul", "unique_factorization_monoid.factors_unique", "units.coe_mul", ...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unit_mul_pow_congr_unit {ϖ : R} (hirr : irreducible ϖ) (u v : Rˣ) (m n : ℕ) (h : ↑u * ϖ ^ m = v * ϖ ^ n) : u = v
begin obtain rfl : m = n := unit_mul_pow_congr_pow hirr hirr u v m n h, rw ← sub_eq_zero at h, rw [← sub_mul, mul_eq_zero] at h, cases h, { rw sub_eq_zero at h, exact_mod_cast h }, { apply (hirr.ne_zero (pow_eq_zero h)).elim, } end
lemma
discrete_valuation_ring.unit_mul_pow_congr_unit
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "irreducible", "mul_eq_zero", "pow_eq_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val (R : Type u) [comm_ring R] [is_domain R] [discrete_valuation_ring R] : add_valuation R part_enat
add_valuation (classical.some_spec (exists_prime R))
def
discrete_valuation_ring.add_val
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "add_valuation", "comm_ring", "discrete_valuation_ring", "is_domain", "part_enat" ]
The `part_enat`-valued additive valuation on a DVR
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_def (r : R) (u : Rˣ) {ϖ : R} (hϖ : irreducible ϖ) (n : ℕ) (hr : r = u * ϖ ^ n) : add_val R r = n
by rw [add_val, add_valuation_apply, hr, eq_of_associated_left (associated_of_irreducible R hϖ (classical.some_spec (exists_prime R)).irreducible), eq_of_associated_right (associated.symm ⟨u, mul_comm _ _⟩), multiplicity_pow_self_of_prime (principal_ideal_ring.irreducible_iff_prime.1 hϖ)]
lemma
discrete_valuation_ring.add_val_def
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "associated.symm", "irreducible", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_def' (u : Rˣ) {ϖ : R} (hϖ : irreducible ϖ) (n : ℕ) : add_val R ((u : R) * ϖ ^ n) = n
add_val_def _ u hϖ n rfl
lemma
discrete_valuation_ring.add_val_def'
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "irreducible" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_zero : add_val R 0 = ⊤
(add_val R).map_zero
lemma
discrete_valuation_ring.add_val_zero
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_one : add_val R 1 = 0
(add_val R).map_one
lemma
discrete_valuation_ring.add_val_one
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "map_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_uniformizer {ϖ : R} (hϖ : irreducible ϖ) : add_val R ϖ = 1
by simpa only [one_mul, eq_self_iff_true, units.coe_one, pow_one, forall_true_left, nat.cast_one] using add_val_def ϖ 1 hϖ 1
lemma
discrete_valuation_ring.add_val_uniformizer
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "forall_true_left", "irreducible", "nat.cast_one", "one_mul", "pow_one", "units.coe_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_mul {a b : R} : add_val R (a * b) = add_val R a + add_val R b
(add_val R).map_mul _ _
lemma
discrete_valuation_ring.add_val_mul
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_pow (a : R) (n : ℕ) : add_val R (a ^ n) = n • add_val R a
(add_val R).map_pow _ _
lemma
discrete_valuation_ring.add_val_pow
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "map_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.irreducible.add_val_pow {ϖ : R} (h : irreducible ϖ) (n : ℕ) : add_val R (ϖ ^ n) = n
by rw [add_val_pow, add_val_uniformizer h, nsmul_one]
lemma
irreducible.add_val_pow
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "irreducible", "nsmul_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_eq_top_iff {a : R} : add_val R a = ⊤ ↔ a = 0
begin have hi := (classical.some_spec (exists_prime R)).irreducible, split, { contrapose, intro h, obtain ⟨n, ha⟩ := associated_pow_irreducible h hi, obtain ⟨u, rfl⟩ := ha.symm, rw [mul_comm, add_val_def' u hi n], exact part_enat.coe_ne_top _ }, { rintro rfl, exact add_val_zero } end
lemma
discrete_valuation_ring.add_val_eq_top_iff
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "irreducible", "mul_comm", "part_enat.coe_ne_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_le_iff_dvd {a b : R} : add_val R a ≤ add_val R b ↔ a ∣ b
begin have hp := classical.some_spec (exists_prime R), split; intro h, { by_cases ha0 : a = 0, { rw [ha0, add_val_zero, top_le_iff, add_val_eq_top_iff] at h, rw h, apply dvd_zero }, obtain ⟨n, ha⟩ := associated_pow_irreducible ha0 hp.irreducible, rw [add_val, add_valuation_apply, add_valua...
lemma
discrete_valuation_ring.add_val_le_iff_dvd
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[ "dvd_zero", "top_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_val_add {a b : R} : min (add_val R a) (add_val R b) ≤ add_val R (a + b)
(add_val R).map_add _ _
lemma
discrete_valuation_ring.add_val_add
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/basic.lean
[ "ring_theory.principal_ideal_domain", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "ring_theory.valuation.basic", "linear_algebra.adic_completion" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_maximal_ideal_pow_eq_of_principal [is_noetherian_ring R] [local_ring R] [is_domain R] (h : ¬ is_field R) (h' : (maximal_ideal R).is_principal) (I : ideal R) (hI : I ≠ ⊥) : ∃ n : ℕ, I = (maximal_ideal R) ^ n
begin classical, unfreezingI { obtain ⟨x, hx : _ = ideal.span _⟩ := h' }, by_cases hI' : I = ⊤, { use 0, rw [pow_zero, hI', ideal.one_eq_top] }, have H : ∀ r : R, ¬ (is_unit r) ↔ x ∣ r := λ r, (set_like.ext_iff.mp hx r).trans ideal.mem_span_singleton, have : x ≠ 0, { rintro rfl, apply ring.ne_bot_of...
lemma
exists_maximal_ideal_pow_eq_of_principal
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/tfae.lean
[ "ring_theory.ideal.cotangent", "ring_theory.dedekind_domain.basic", "ring_theory.valuation.valuation_ring", "ring_theory.nakayama" ]
[ "associated", "associated.mul_mul", "by_contra", "discrete_valuation_ring.irreducible_of_span_eq_maximal_ideal", "dvd_refl", "eq_bot_iff", "eq_or_ne", "ideal", "ideal.mem_span_singleton", "ideal.one_eq_top", "ideal.pow_le_pow", "ideal.pow_mem_pow", "ideal.span", "ideal.span_le", "ideal.s...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
maximal_ideal_is_principal_of_is_dedekind_domain [local_ring R] [is_domain R] [is_dedekind_domain R] : (maximal_ideal R).is_principal
begin classical, by_cases ne_bot : maximal_ideal R = ⊥, { rw ne_bot, apply_instance }, obtain ⟨a, ha₁, ha₂⟩ : ∃ a ∈ maximal_ideal R, a ≠ (0 : R), { by_contra h', push_neg at h', apply ne_bot, rwa eq_bot_iff }, have hle : ideal.span {a} ≤ maximal_ideal R, { rwa [ideal.span_le, set.singleton_subset_iff] }, ...
lemma
maximal_ideal_is_principal_of_is_dedekind_domain
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/tfae.lean
[ "ring_theory.ideal.cotangent", "ring_theory.dedekind_domain.basic", "ring_theory.valuation.valuation_ring", "ring_theory.nakayama" ]
[ "Inf_le", "algebra.of_id", "algebra_map", "by_contra", "distrib_mul_action.to_linear_map", "div_eq_one_iff_eq", "div_mul_cancel", "eq_bot_iff", "fraction_ring", "ideal.eq_top_iff_one", "ideal.exists_radical_pow_le_of_fg", "ideal.is_maximal.ne_top", "ideal.mem_span_singleton'", "ideal.mul_m...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discrete_valuation_ring.tfae [is_noetherian_ring R] [local_ring R] [is_domain R] (h : ¬ is_field R) : tfae [discrete_valuation_ring R, valuation_ring R, is_dedekind_domain R, is_integrally_closed R ∧ ∃! P : ideal R, P ≠ ⊥ ∧ P.is_prime, (maximal_ideal R).is_principal, finite_dimensional.finrank (...
begin have ne_bot := ring.ne_bot_of_is_maximal_of_not_is_field (maximal_ideal.is_maximal R) h, classical, rw finrank_eq_one_iff', tfae_have : 1 → 2, { introI _, apply_instance }, tfae_have : 2 → 1, { introI _, haveI := is_bezout.to_gcd_domain R, haveI : unique_factorization_monoid R := ufm_of_gcd_...
lemma
discrete_valuation_ring.tfae
ring_theory.discrete_valuation_ring
src/ring_theory/discrete_valuation_ring/tfae.lean
[ "ring_theory.ideal.cotangent", "ring_theory.dedekind_domain.basic", "ring_theory.valuation.valuation_ring", "ring_theory.nakayama" ]
[ "bot_le", "bot_ne_top", "discrete_valuation_ring", "discrete_valuation_ring.iff_pid_with_one_nonzero_prime", "discrete_valuation_ring.of_ufd_of_unique_irreducible", "exists_maximal_ideal_pow_eq_of_principal", "finite_dimensional.finrank", "finrank_eq_one_iff'", "finset.coe_singleton", "ideal", "...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_ring (𝒜 : ι → σ) extends set_like.graded_monoid 𝒜, direct_sum.decomposition 𝒜.
class
graded_ring
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "direct_sum.decomposition", "set_like.graded_monoid" ]
An internally-graded `R`-algebra `A` is one that can be decomposed into a collection of `submodule R A`s indexed by `ι` such that the canonical map `A → ⨁ i, 𝒜 i` is bijective and respects multiplication, i.e. the product of an element of degree `i` and an element of degree `j` is an element of degree `i + j`. Note t...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_ring_equiv : A ≃+* ⨁ i, 𝒜 i
ring_equiv.symm { map_mul' := (coe_ring_hom 𝒜).map_mul, map_add' := (coe_ring_hom 𝒜).map_add, ..(decompose_add_equiv 𝒜).symm }
def
direct_sum.decompose_ring_equiv
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "map_mul", "ring_equiv.symm" ]
If `A` is graded by `ι` with degree `i` component `𝒜 i`, then it is isomorphic as a ring to a direct sum of components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_one : decompose 𝒜 (1 : A) = 1
map_one (decompose_ring_equiv 𝒜)
lemma
direct_sum.decompose_one
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "map_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_symm_one : (decompose 𝒜).symm 1 = (1 : A)
map_one (decompose_ring_equiv 𝒜).symm
lemma
direct_sum.decompose_symm_one
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "map_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_mul (x y : A) : decompose 𝒜 (x * y) = decompose 𝒜 x * decompose 𝒜 y
map_mul (decompose_ring_equiv 𝒜) x y
lemma
direct_sum.decompose_mul
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_symm_mul (x y : ⨁ i, 𝒜 i) : (decompose 𝒜).symm (x * y) = (decompose 𝒜).symm x * (decompose 𝒜).symm y
map_mul (decompose_ring_equiv 𝒜).symm x y
lemma
direct_sum.decompose_symm_mul
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "map_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_ring.proj (i : ι) : A →+ A
(add_submonoid_class.subtype (𝒜 i)).comp $ (dfinsupp.eval_add_monoid_hom i).comp $ ring_hom.to_add_monoid_hom $ ring_equiv.to_ring_hom $ direct_sum.decompose_ring_equiv 𝒜
def
graded_ring.proj
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "dfinsupp.eval_add_monoid_hom", "direct_sum.decompose_ring_equiv", "ring_equiv.to_ring_hom" ]
The projection maps of a graded ring
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_ring.proj_apply (i : ι) (r : A) : graded_ring.proj 𝒜 i r = (decompose 𝒜 r : ⨁ i, 𝒜 i) i
rfl
lemma
graded_ring.proj_apply
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "graded_ring.proj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_ring.proj_recompose (a : ⨁ i, 𝒜 i) (i : ι) : graded_ring.proj 𝒜 i ((decompose 𝒜).symm a) = (decompose 𝒜).symm (direct_sum.of _ i (a i))
by rw [graded_ring.proj_apply, decompose_symm_of, equiv.apply_symm_apply]
lemma
graded_ring.proj_recompose
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "direct_sum.of", "equiv.apply_symm_apply", "graded_ring.proj", "graded_ring.proj_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_ring.mem_support_iff [Π i (x : 𝒜 i), decidable (x ≠ 0)] (r : A) (i : ι) : i ∈ (decompose 𝒜 r).support ↔ graded_ring.proj 𝒜 i r ≠ 0
dfinsupp.mem_support_iff.trans zero_mem_class.coe_eq_zero.not.symm
lemma
graded_ring.mem_support_iff
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "graded_ring.proj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_add_of_left_mem [add_left_cancel_monoid ι] [graded_ring 𝒜] {a b : A} (a_mem : a ∈ 𝒜 i) : (decompose 𝒜 (a * b) (i + j) : A) = a * decompose 𝒜 b j
by { lift a to 𝒜 i using a_mem, rw [decompose_mul, decompose_coe, coe_of_mul_apply_add] }
lemma
direct_sum.coe_decompose_mul_add_of_left_mem
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "add_left_cancel_monoid", "graded_ring", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_add_of_right_mem [add_right_cancel_monoid ι] [graded_ring 𝒜] {a b : A} (b_mem : b ∈ 𝒜 j) : (decompose 𝒜 (a * b) (i + j) : A) = decompose 𝒜 a i * b
by { lift b to 𝒜 j using b_mem, rw [decompose_mul, decompose_coe, coe_mul_of_apply_add] }
lemma
direct_sum.coe_decompose_mul_add_of_right_mem
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "add_right_cancel_monoid", "graded_ring", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_mul_add_left [add_left_cancel_monoid ι] [graded_ring 𝒜] (a : 𝒜 i) {b : A} : decompose 𝒜 (↑a * b) (i + j) = @graded_monoid.ghas_mul.mul ι (λ i, 𝒜 i) _ _ _ _ a (decompose 𝒜 b j)
subtype.ext $ coe_decompose_mul_add_of_left_mem 𝒜 a.2
lemma
direct_sum.decompose_mul_add_left
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "add_left_cancel_monoid", "graded_ring", "subtype.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_mul_add_right [add_right_cancel_monoid ι] [graded_ring 𝒜] {a : A} (b : 𝒜 j) : decompose 𝒜 (a * ↑b) (i + j) = @graded_monoid.ghas_mul.mul ι (λ i, 𝒜 i) _ _ _ _ (decompose 𝒜 a i) b
subtype.ext $ coe_decompose_mul_add_of_right_mem 𝒜 b.2
lemma
direct_sum.decompose_mul_add_right
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "add_right_cancel_monoid", "graded_ring", "subtype.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_algebra
graded_ring 𝒜
def
graded_algebra
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "graded_ring" ]
A special case of `graded_ring` with `σ = submodule R A`. This is useful both because it can avoid typeclass search, and because it provides a more concise name.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_algebra.of_alg_hom [set_like.graded_monoid 𝒜] (decompose : A →ₐ[R] ⨁ i, 𝒜 i) (right_inv : (direct_sum.coe_alg_hom 𝒜).comp decompose = alg_hom.id R A) (left_inv : ∀ i (x : 𝒜 i), decompose (x : A) = direct_sum.of (λ i, ↥(𝒜 i)) i x) : graded_algebra 𝒜
{ decompose' := decompose, left_inv := alg_hom.congr_fun right_inv, right_inv := begin suffices : decompose.comp (direct_sum.coe_alg_hom 𝒜) = alg_hom.id _ _, from alg_hom.congr_fun this, ext i x : 2, exact (decompose.congr_arg $ direct_sum.coe_alg_hom_of _ _ _).trans (left_inv i x), end}
def
graded_algebra.of_alg_hom
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "alg_hom.congr_fun", "alg_hom.id", "direct_sum.coe_alg_hom", "direct_sum.coe_alg_hom_of", "direct_sum.of", "graded_algebra", "set_like.graded_monoid" ]
A helper to construct a `graded_algebra` when the `set_like.graded_monoid` structure is already available. This makes the `left_inv` condition easier to prove, and phrases the `right_inv` condition in a way that allows custom `@[ext]` lemmas to apply. See note [reducible non-instances].
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
decompose_alg_equiv : A ≃ₐ[R] ⨁ i, 𝒜 i
alg_equiv.symm { map_mul' := (coe_alg_hom 𝒜).map_mul, map_add' := (coe_alg_hom 𝒜).map_add, commutes' := (coe_alg_hom 𝒜).commutes, ..(decompose_add_equiv 𝒜).symm }
def
direct_sum.decompose_alg_equiv
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "alg_equiv.symm", "map_mul" ]
If `A` is graded by `ι` with degree `i` component `𝒜 i`, then it is isomorphic as an algebra to a direct sum of components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_algebra.proj (𝒜 : ι → submodule R A) [graded_algebra 𝒜] (i : ι) : A →ₗ[R] A
(𝒜 i).subtype.comp $ (dfinsupp.lapply i).comp $ (decompose_alg_equiv 𝒜).to_alg_hom.to_linear_map
def
graded_algebra.proj
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "dfinsupp.lapply", "graded_algebra", "submodule" ]
The projection maps of graded algebra
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_algebra.proj_apply (i : ι) (r : A) : graded_algebra.proj 𝒜 i r = (decompose 𝒜 r : ⨁ i, 𝒜 i) i
rfl
lemma
graded_algebra.proj_apply
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "graded_algebra.proj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_algebra.proj_recompose (a : ⨁ i, 𝒜 i) (i : ι) : graded_algebra.proj 𝒜 i ((decompose 𝒜).symm a) = (decompose 𝒜).symm (of _ i (a i))
by rw [graded_algebra.proj_apply, decompose_symm_of, equiv.apply_symm_apply]
lemma
graded_algebra.proj_recompose
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "equiv.apply_symm_apply", "graded_algebra.proj", "graded_algebra.proj_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_algebra.mem_support_iff [decidable_eq A] (r : A) (i : ι) : i ∈ (decompose 𝒜 r).support ↔ graded_algebra.proj 𝒜 i r ≠ 0
dfinsupp.mem_support_iff.trans submodule.coe_eq_zero.not.symm
lemma
graded_algebra.mem_support_iff
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "graded_algebra.proj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
graded_ring.proj_zero_ring_hom : A →+* A
{ to_fun := λ a, decompose 𝒜 a 0, map_one' := decompose_of_mem_same 𝒜 one_mem, map_zero' := by { rw decompose_zero, refl }, map_add' := λ _ _, by { rw decompose_add, refl }, map_mul' := begin refine direct_sum.decomposition.induction_on 𝒜 (λ x, _) _ _, { simp only [zero_mul, decompose_zero, zero_appl...
def
graded_ring.proj_zero_ring_hom
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "direct_sum.decomposition.induction_on", "mul_zero", "not_and_distrib", "subtype.coe_mk", "zero_mul" ]
If `A` is graded by a canonically ordered add monoid, then the projection map `x ↦ x₀` is a ring homomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_of_left_mem_of_not_le (a_mem : a ∈ 𝒜 i) (h : ¬ i ≤ n) : (decompose 𝒜 (a * b) n : A) = 0
by { lift a to 𝒜 i using a_mem, rwa [decompose_mul, decompose_coe, coe_of_mul_apply_of_not_le] }
lemma
direct_sum.coe_decompose_mul_of_left_mem_of_not_le
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_of_right_mem_of_not_le (b_mem : b ∈ 𝒜 i) (h : ¬ i ≤ n) : (decompose 𝒜 (a * b) n : A) = 0
by { lift b to 𝒜 i using b_mem, rwa [decompose_mul, decompose_coe, coe_mul_of_apply_of_not_le] }
lemma
direct_sum.coe_decompose_mul_of_right_mem_of_not_le
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_of_left_mem_of_le (a_mem : a ∈ 𝒜 i) (h : i ≤ n) : (decompose 𝒜 (a * b) n : A) = a * decompose 𝒜 b (n - i)
by { lift a to 𝒜 i using a_mem, rwa [decompose_mul, decompose_coe, coe_of_mul_apply_of_le] }
lemma
direct_sum.coe_decompose_mul_of_left_mem_of_le
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_of_right_mem_of_le (b_mem : b ∈ 𝒜 i) (h : i ≤ n) : (decompose 𝒜 (a * b) n : A) = decompose 𝒜 a (n - i) * b
by { lift b to 𝒜 i using b_mem, rwa [decompose_mul, decompose_coe, coe_mul_of_apply_of_le] }
lemma
direct_sum.coe_decompose_mul_of_right_mem_of_le
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_of_left_mem (n) [decidable (i ≤ n)] (a_mem : a ∈ 𝒜 i) : (decompose 𝒜 (a * b) n : A) = if i ≤ n then a * decompose 𝒜 b (n - i) else 0
by { lift a to 𝒜 i using a_mem, rwa [decompose_mul, decompose_coe, coe_of_mul_apply] }
lemma
direct_sum.coe_decompose_mul_of_left_mem
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_decompose_mul_of_right_mem (n) [decidable (i ≤ n)] (b_mem : b ∈ 𝒜 i) : (decompose 𝒜 (a * b) n : A) = if i ≤ n then decompose 𝒜 a (n - i) * b else 0
by { lift b to 𝒜 i using b_mem, rwa [decompose_mul, decompose_coe, coe_mul_of_apply] }
lemma
direct_sum.coe_decompose_mul_of_right_mem
ring_theory.graded_algebra
src/ring_theory/graded_algebra/basic.lean
[ "algebra.direct_sum.algebra", "algebra.direct_sum.decomposition", "algebra.direct_sum.internal", "algebra.direct_sum.ring" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.is_homogeneous : Prop
∀ (i : ι) ⦃r : A⦄, r ∈ I → (direct_sum.decompose 𝒜 r i : A) ∈ I
def
ideal.is_homogeneous
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "direct_sum.decompose" ]
An `I : ideal A` is homogeneous if for every `r ∈ I`, all homogeneous components of `r` are in `I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal extends submodule A A
(is_homogeneous' : ideal.is_homogeneous 𝒜 to_submodule)
structure
homogeneous_ideal
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.is_homogeneous", "submodule" ]
For any `semiring A`, we collect the homogeneous ideals of `A` into a type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal.to_ideal (I : homogeneous_ideal 𝒜) : ideal A
I.to_submodule
def
homogeneous_ideal.to_ideal
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal", "ideal" ]
Converting a homogeneous ideal to an ideal
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal.is_homogeneous (I : homogeneous_ideal 𝒜) : I.to_ideal.is_homogeneous 𝒜
I.is_homogeneous'
lemma
homogeneous_ideal.is_homogeneous
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal.to_ideal_injective : function.injective (homogeneous_ideal.to_ideal : homogeneous_ideal 𝒜 → ideal A)
λ ⟨x, hx⟩ ⟨y, hy⟩ (h : x = y), by simp [h]
lemma
homogeneous_ideal.to_ideal_injective
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal", "homogeneous_ideal.to_ideal", "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal.set_like : set_like (homogeneous_ideal 𝒜) A
{ coe := λ I, I.to_ideal, coe_injective' := λ I J h, homogeneous_ideal.to_ideal_injective $ set_like.coe_injective h }
instance
homogeneous_ideal.set_like
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal", "homogeneous_ideal.to_ideal_injective", "set_like", "set_like.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal.ext {I J : homogeneous_ideal 𝒜} (h : I.to_ideal = J.to_ideal) : I = J
homogeneous_ideal.to_ideal_injective h
lemma
homogeneous_ideal.ext
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal", "homogeneous_ideal.to_ideal_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal.mem_iff {I : homogeneous_ideal 𝒜} {x : A} : x ∈ I.to_ideal ↔ x ∈ I
iff.rfl
lemma
homogeneous_ideal.mem_iff
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.homogeneous_core' (I : ideal A) : ideal A
ideal.span (coe '' ((coe : subtype (is_homogeneous 𝒜) → A) ⁻¹' I))
def
ideal.homogeneous_core'
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal", "ideal.span" ]
For any `I : ideal A`, not necessarily homogeneous, `I.homogeneous_core' 𝒜` is the largest homogeneous ideal of `A` contained in `I`, as an ideal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.homogeneous_core'_mono : monotone (ideal.homogeneous_core' 𝒜)
λ I J I_le_J, ideal.span_mono $ set.image_subset _ $ λ x, @I_le_J _
lemma
ideal.homogeneous_core'_mono
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.homogeneous_core'", "ideal.span_mono", "monotone", "set.image_subset" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.homogeneous_core'_le : I.homogeneous_core' 𝒜 ≤ I
ideal.span_le.2 $ image_preimage_subset _ _
lemma
ideal.homogeneous_core'_le
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.is_homogeneous_iff_forall_subset : I.is_homogeneous 𝒜 ↔ ∀ i, (I : set A) ⊆ graded_ring.proj 𝒜 i ⁻¹' I
iff.rfl
lemma
ideal.is_homogeneous_iff_forall_subset
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "graded_ring.proj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.is_homogeneous_iff_subset_Inter : I.is_homogeneous 𝒜 ↔ (I : set A) ⊆ ⋂ i, graded_ring.proj 𝒜 i ⁻¹' ↑I
subset_Inter_iff.symm
lemma
ideal.is_homogeneous_iff_subset_Inter
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "graded_ring.proj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.mul_homogeneous_element_mem_of_mem {I : ideal A} (r x : A) (hx₁ : is_homogeneous 𝒜 x) (hx₂ : x ∈ I) (j : ι) : graded_ring.proj 𝒜 j (r * x) ∈ I
begin classical, rw [←direct_sum.sum_support_decompose 𝒜 r, finset.sum_mul, map_sum], apply ideal.sum_mem, intros k hk, obtain ⟨i, hi⟩ := hx₁, have mem₁ : (direct_sum.decompose 𝒜 r k : A) * x ∈ 𝒜 (k + i) := graded_monoid.mul_mem (set_like.coe_mem _) hi, erw [graded_ring.proj_apply, direct_sum.decom...
lemma
ideal.mul_homogeneous_element_mem_of_mem
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "direct_sum.decompose", "direct_sum.decompose_of_mem", "finset.sum_mul", "graded_ring.proj", "graded_ring.proj_apply", "ideal", "ideal.sum_mem", "set_like.coe_mem", "set_like.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.is_homogeneous_span (s : set A) (h : ∀ x ∈ s, is_homogeneous 𝒜 x) : (ideal.span s).is_homogeneous 𝒜
begin rintros i r hr, rw [ideal.span, finsupp.span_eq_range_total] at hr, rw linear_map.mem_range at hr, obtain ⟨s, rfl⟩ := hr, rw [finsupp.total_apply, finsupp.sum, decompose_sum, dfinsupp.finset_sum_apply, add_submonoid_class.coe_finset_sum], refine ideal.sum_mem _ _, rintros z hz1, rw [smul_eq_mu...
lemma
ideal.is_homogeneous_span
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "dfinsupp.finset_sum_apply", "finsupp.span_eq_range_total", "finsupp.total_apply", "ideal.mul_homogeneous_element_mem_of_mem", "ideal.span", "ideal.subset_span", "ideal.sum_mem", "linear_map.mem_range", "smul_eq_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.homogeneous_core : homogeneous_ideal 𝒜
⟨ideal.homogeneous_core' 𝒜 I, ideal.is_homogeneous_span _ _ (λ x h, by { rw [subtype.image_preimage_coe] at h, exact h.2 })⟩
def
ideal.homogeneous_core
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal", "ideal.is_homogeneous_span", "subtype.image_preimage_coe" ]
For any `I : ideal A`, not necessarily homogeneous, `I.homogeneous_core' 𝒜` is the largest homogeneous ideal of `A` contained in `I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.homogeneous_core_mono : monotone (ideal.homogeneous_core 𝒜)
ideal.homogeneous_core'_mono 𝒜
lemma
ideal.homogeneous_core_mono
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.homogeneous_core", "ideal.homogeneous_core'_mono", "monotone" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.to_ideal_homogeneous_core_le : (I.homogeneous_core 𝒜).to_ideal ≤ I
ideal.homogeneous_core'_le 𝒜 I
lemma
ideal.to_ideal_homogeneous_core_le
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.homogeneous_core'_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.mem_homogeneous_core_of_is_homogeneous_of_mem {x : A} (h : set_like.is_homogeneous 𝒜 x) (hmem : x ∈ I) : x ∈ I.homogeneous_core 𝒜
ideal.subset_span ⟨⟨x, h⟩, hmem, rfl⟩
lemma
ideal.mem_homogeneous_core_of_is_homogeneous_of_mem
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.subset_span", "set_like.is_homogeneous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.is_homogeneous.to_ideal_homogeneous_core_eq_self (h : I.is_homogeneous 𝒜) : (I.homogeneous_core 𝒜).to_ideal = I
begin apply le_antisymm (I.homogeneous_core'_le 𝒜) _, intros x hx, classical, rw ←direct_sum.sum_support_decompose 𝒜 x, exact ideal.sum_mem _ (λ j hj, ideal.subset_span ⟨⟨_, is_homogeneous_coe _⟩, h _ hx, rfl⟩) end
lemma
ideal.is_homogeneous.to_ideal_homogeneous_core_eq_self
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.subset_span", "ideal.sum_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homogeneous_ideal.to_ideal_homogeneous_core_eq_self (I : homogeneous_ideal 𝒜) : I.to_ideal.homogeneous_core 𝒜 = I
by ext1; convert ideal.is_homogeneous.to_ideal_homogeneous_core_eq_self I.is_homogeneous
lemma
homogeneous_ideal.to_ideal_homogeneous_core_eq_self
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal", "ideal.is_homogeneous.to_ideal_homogeneous_core_eq_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.is_homogeneous.iff_eq : I.is_homogeneous 𝒜 ↔ (I.homogeneous_core 𝒜).to_ideal = I
⟨ λ hI, hI.to_ideal_homogeneous_core_eq_self, λ hI, hI ▸ (ideal.homogeneous_core 𝒜 I).2 ⟩
lemma
ideal.is_homogeneous.iff_eq
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.homogeneous_core" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.is_homogeneous.iff_exists : I.is_homogeneous 𝒜 ↔ ∃ (S : set (homogeneous_submonoid 𝒜)), I = ideal.span (coe '' S)
begin rw [ideal.is_homogeneous.iff_eq, eq_comm], exact ((set.image_preimage.compose (submodule.gi _ _).gc).exists_eq_l _).symm, end
lemma
ideal.is_homogeneous.iff_exists
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.is_homogeneous.iff_eq", "ideal.span", "submodule.gi" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bot : ideal.is_homogeneous 𝒜 ⊥
λ i r hr, begin simp only [ideal.mem_bot] at hr, rw [hr, decompose_zero, zero_apply], apply ideal.zero_mem end
lemma
ideal.is_homogeneous.bot
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.is_homogeneous", "ideal.mem_bot", "ideal.zero_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
top : ideal.is_homogeneous 𝒜 ⊤
λ i r hr, by simp only [submodule.mem_top]
lemma
ideal.is_homogeneous.top
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal.is_homogeneous", "submodule.mem_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inf {I J : ideal A} (HI : I.is_homogeneous 𝒜) (HJ : J.is_homogeneous 𝒜) : (I ⊓ J).is_homogeneous 𝒜
λ i r hr, ⟨HI _ hr.1, HJ _ hr.2⟩
lemma
ideal.is_homogeneous.inf
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sup {I J : ideal A} (HI : I.is_homogeneous 𝒜) (HJ : J.is_homogeneous 𝒜) : (I ⊔ J).is_homogeneous 𝒜
begin rw iff_exists at HI HJ ⊢, obtain ⟨⟨s₁, rfl⟩, ⟨s₂, rfl⟩⟩ := ⟨HI, HJ⟩, refine ⟨s₁ ∪ s₂, _⟩, rw [set.image_union], exact (submodule.span_union _ _).symm, end
lemma
ideal.is_homogeneous.sup
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal", "set.image_union", "submodule.span_union" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
supr {κ : Sort*} {f : κ → ideal A} (h : ∀ i, (f i).is_homogeneous 𝒜) : (⨆ i, f i).is_homogeneous 𝒜
begin simp_rw iff_exists at h ⊢, choose s hs using h, refine ⟨⋃ i, s i, _⟩, simp_rw [set.image_Union, ideal.span_Union], congr', exact funext hs, end
lemma
ideal.is_homogeneous.supr
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal", "ideal.span_Union", "set.image_Union", "supr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
infi {κ : Sort*} {f : κ → ideal A} (h : ∀ i, (f i).is_homogeneous 𝒜) : (⨅ i, f i).is_homogeneous 𝒜
begin intros i x hx, simp only [ideal.mem_infi] at ⊢ hx, exact λ j, h _ _ (hx j), end
lemma
ideal.is_homogeneous.infi
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal", "ideal.mem_infi", "infi" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
supr₂ {κ : Sort*} {κ' : κ → Sort*} {f : Π i, κ' i → ideal A} (h : ∀ i j, (f i j).is_homogeneous 𝒜) : (⨆ i j, f i j).is_homogeneous 𝒜
is_homogeneous.supr $ λ i, is_homogeneous.supr $ h i
lemma
ideal.is_homogeneous.supr₂
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
infi₂ {κ : Sort*} {κ' : κ → Sort*} {f : Π i, κ' i → ideal A} (h : ∀ i j, (f i j).is_homogeneous 𝒜) : (⨅ i j, f i j).is_homogeneous 𝒜
is_homogeneous.infi $ λ i, is_homogeneous.infi $ h i
lemma
ideal.is_homogeneous.infi₂
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Sup {ℐ : set (ideal A)} (h : ∀ I ∈ ℐ, ideal.is_homogeneous 𝒜 I) : (Sup ℐ).is_homogeneous 𝒜
by { rw Sup_eq_supr, exact supr₂ h }
lemma
ideal.is_homogeneous.Sup
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "Sup_eq_supr", "ideal", "ideal.is_homogeneous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Inf {ℐ : set (ideal A)} (h : ∀ I ∈ ℐ, ideal.is_homogeneous 𝒜 I) : (Inf ℐ).is_homogeneous 𝒜
by { rw Inf_eq_infi, exact infi₂ h }
lemma
ideal.is_homogeneous.Inf
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "Inf_eq_infi", "ideal", "ideal.is_homogeneous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_top : ((⊤ : homogeneous_ideal 𝒜) : set A) = univ
rfl
lemma
homogeneous_ideal.coe_top
ring_theory.graded_algebra
src/ring_theory/graded_algebra/homogeneous_ideal.lean
[ "ring_theory.ideal.basic", "ring_theory.ideal.operations", "linear_algebra.finsupp", "ring_theory.graded_algebra.basic" ]
[ "homogeneous_ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83