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degree_le_eq_span_X_pow {n : ℕ} : degree_le R n = submodule.span R ↑((finset.range (n+1)).image (λ n, (X : R[X])^n))
begin apply le_antisymm, { intros p hp, replace hp := mem_degree_le.1 hp, rw [← polynomial.sum_monomial_eq p, polynomial.sum], refine submodule.sum_mem _ (λ k hk, _), show monomial _ _ ∈ _, have := with_bot.coe_le_coe.1 (finset.sup_le_iff.1 hp k hk), rw [← C_mul_X_pow_eq_monomial, C_mul'], r...
theorem
polynomial.degree_le_eq_span_X_pow
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finset.coe_image", "finset.range", "polynomial.sum", "polynomial.sum_monomial_eq", "set.image_subset_iff", "submodule.smul_mem", "submodule.span", "submodule.span_le", "submodule.subset_span", "submodule.sum_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_degree_lt {n : ℕ} {f : R[X]} : f ∈ degree_lt R n ↔ degree f < n
by { simp_rw [degree_lt, submodule.mem_infi, linear_map.mem_ker, degree, finset.max_eq_sup_coe, finset.sup_lt_iff (with_bot.bot_lt_coe n), mem_support_iff, with_bot.coe_lt_coe, lt_iff_not_le, ne, not_imp_not], refl }
theorem
polynomial.mem_degree_lt
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finset.max_eq_sup_coe", "finset.sup_lt_iff", "linear_map.mem_ker", "lt_iff_not_le", "not_imp_not", "submodule.mem_infi", "with_bot.bot_lt_coe", "with_bot.coe_lt_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
degree_lt_mono {m n : ℕ} (H : m ≤ n) : degree_lt R m ≤ degree_lt R n
λ f hf, mem_degree_lt.2 (lt_of_lt_of_le (mem_degree_lt.1 hf) $ with_bot.coe_le_coe.2 H)
theorem
polynomial.degree_lt_mono
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
degree_lt_eq_span_X_pow {n : ℕ} : degree_lt R n = submodule.span R ↑((finset.range n).image (λ n, X^n) : finset R[X])
begin apply le_antisymm, { intros p hp, replace hp := mem_degree_lt.1 hp, rw [← polynomial.sum_monomial_eq p, polynomial.sum], refine submodule.sum_mem _ (λ k hk, _), show monomial _ _ ∈ _, have := with_bot.coe_lt_coe.1 ((finset.sup_lt_iff $ with_bot.bot_lt_coe n).1 hp k hk), rw [← C_mul_X_pow_e...
theorem
polynomial.degree_lt_eq_span_X_pow
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finset", "finset.coe_image", "finset.range", "finset.sup_lt_iff", "polynomial.sum", "polynomial.sum_monomial_eq", "set.image_subset_iff", "submodule.smul_mem", "submodule.span", "submodule.span_le", "submodule.subset_span", "submodule.sum_mem", "with_bot.bot_lt_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
degree_lt_equiv (R) [semiring R] (n : ℕ) : degree_lt R n ≃ₗ[R] (fin n → R)
{ to_fun := λ p n, (↑p : R[X]).coeff n, inv_fun := λ f, ⟨∑ i : fin n, monomial i (f i), (degree_lt R n).sum_mem (λ i _, mem_degree_lt.mpr (lt_of_le_of_lt (degree_monomial_le i (f i)) (with_bot.coe_lt_coe.mpr i.is_lt)))⟩, map_add' := λ p q, by { ext, rw [submodule.coe_add, coeff_add], refl }, map_smul' :...
def
polynomial.degree_lt_equiv
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "fin.ext_iff", "finset.mem_univ", "inv_fun", "linear_map.map_zero", "semiring", "submodule.coe_add", "submodule.coe_mk", "submodule.coe_smul", "with_bot.coe_lt_coe" ]
The first `n` coefficients on `degree_lt n` form a linear equivalence with `fin n → R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
degree_lt_equiv_eq_zero_iff_eq_zero {n : ℕ} {p : R[X]} (hp : p ∈ degree_lt R n) : degree_lt_equiv _ _ ⟨p, hp⟩ = 0 ↔ p = 0
by rw [linear_equiv.map_eq_zero_iff, submodule.mk_eq_zero]
theorem
polynomial.degree_lt_equiv_eq_zero_iff_eq_zero
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "linear_equiv.map_eq_zero_iff", "submodule.mk_eq_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval_eq_sum_degree_lt_equiv {n : ℕ} {p : R[X]} (hp : p ∈ degree_lt R n) (x : R) : p.eval x = ∑ i, degree_lt_equiv _ _ ⟨p, hp⟩ i * (x ^ (i : ℕ))
begin simp_rw [eval_eq_sum], exact (sum_fin _ (by simp_rw [zero_mul, forall_const]) (mem_degree_lt.mp hp)).symm end
theorem
polynomial.eval_eq_sum_degree_lt_equiv
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "forall_const", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frange (p : R[X]) : finset R
finset.image (λ n, p.coeff n) p.support
def
polynomial.frange
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finset", "finset.image" ]
The finset of nonzero coefficients of a polynomial.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frange_zero : frange (0 : R[X]) = ∅
rfl
lemma
polynomial.frange_zero
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_frange_iff {p : R[X]} {c : R} : c ∈ p.frange ↔ ∃ n ∈ p.support, c = p.coeff n
by simp [frange, eq_comm]
lemma
polynomial.mem_frange_iff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frange_one : frange (1 : R[X]) ⊆ {1}
begin simp [frange, finset.image_subset_iff], simp only [← C_1, coeff_C], assume n hn, simp only [exists_prop, ite_eq_right_iff, not_forall] at hn, simp [hn], end
lemma
polynomial.frange_one
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "exists_prop", "finset.image_subset_iff", "ite_eq_right_iff", "not_forall" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_mem_frange (p : R[X]) (n : ℕ) (h : p.coeff n ≠ 0) : p.coeff n ∈ p.frange
begin simp only [frange, exists_prop, mem_support_iff, finset.mem_image, ne.def], exact ⟨n, h, rfl⟩, end
lemma
polynomial.coeff_mem_frange
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "exists_prop", "finset.mem_image" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
geom_sum_X_comp_X_add_one_eq_sum (n : ℕ) : (∑ i in range n, (X : R[X]) ^ i).comp (X + 1) = (finset.range n).sum (λ (i : ℕ), (n.choose (i + 1) : R[X]) * X ^ i)
begin ext i, transitivity (n.choose (i + 1) : R), swap, { simp only [finset_sum_coeff, ← C_eq_nat_cast, coeff_C_mul_X_pow], rw [finset.sum_eq_single i, if_pos rfl], { simp only [@eq_comm _ i, if_false, eq_self_iff_true, implies_true_iff] {contextual := tt}, }, { simp only [nat.lt_add_one_iff, nat.choo...
lemma
polynomial.geom_sum_X_comp_X_add_one_eq_sum
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finset.mem_range", "finset.range", "geom_sum_succ'", "geom_sum_zero", "ih", "nat.cast_add", "nat.cast_zero", "nat.choose_eq_zero_of_lt", "nat.choose_succ_succ", "nat.choose_zero_succ", "nat.lt_add_one_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monic.geom_sum {P : R[X]} (hP : P.monic) (hdeg : 0 < P.nat_degree) {n : ℕ} (hn : n ≠ 0) : (∑ i in range n, P ^ i).monic
begin nontriviality R, cases n, { exact (hn rfl).elim }, rw [geom_sum_succ'], refine (hP.pow _).add_of_left _, refine lt_of_le_of_lt (degree_sum_le _ _) _, rw [finset.sup_lt_iff], { simp only [finset.mem_range, degree_eq_nat_degree (hP.pow _).ne_zero, with_bot.coe_lt_coe, hP.nat_degree_pow], int...
lemma
polynomial.monic.geom_sum
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "bot_lt_iff_ne_bot", "finset.mem_range", "finset.sup_lt_iff", "geom_sum_succ'", "ne_zero", "with_bot.coe_lt_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monic.geom_sum' {P : R[X]} (hP : P.monic) (hdeg : 0 < P.degree) {n : ℕ} (hn : n ≠ 0) : (∑ i in range n, P ^ i).monic
hP.geom_sum (nat_degree_pos_iff_degree_pos.2 hdeg) hn
lemma
polynomial.monic.geom_sum'
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monic_geom_sum_X {n : ℕ} (hn : n ≠ 0) : (∑ i in range n, (X : R[X]) ^ i).monic
begin nontriviality R, apply monic_X.geom_sum _ hn, simpa only [nat_degree_X] using zero_lt_one end
lemma
polynomial.monic_geom_sum_X
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "zero_lt_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restriction (p : R[X]) : polynomial (subring.closure (↑p.frange : set R))
∑ i in p.support, monomial i (⟨p.coeff i, if H : p.coeff i = 0 then H.symm ▸ (subring.closure _).zero_mem else subring.subset_closure (p.coeff_mem_frange _ H)⟩ : (subring.closure (↑p.frange : set R)))
def
polynomial.restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "polynomial", "subring.closure", "subring.subset_closure" ]
Given a polynomial, return the polynomial whose coefficients are in the ring closure of the original coefficients.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_restriction {p : R[X]} {n : ℕ} : ↑(coeff (restriction p) n) = coeff p n
begin simp only [restriction, coeff_monomial, finset_sum_coeff, mem_support_iff, finset.sum_ite_eq', ne.def, ite_not], split_ifs, { rw h, refl }, { refl } end
theorem
polynomial.coeff_restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ite_not" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_restriction' {p : R[X]} {n : ℕ} : (coeff (restriction p) n).1 = coeff p n
coeff_restriction
theorem
polynomial.coeff_restriction'
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_restriction (p : R[X]) : support (restriction p) = support p
begin ext i, simp only [mem_support_iff, not_iff_not, ne.def], conv_rhs { rw [← coeff_restriction] }, exact ⟨λ H, by { rw H, refl }, λ H, subtype.coe_injective H⟩ end
lemma
polynomial.support_restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "not_iff_not", "subtype.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_restriction {R : Type u} [comm_ring R] (p : R[X]) : p.restriction.map (algebra_map _ _) = p
ext $ λ n, by rw [coeff_map, algebra.algebra_map_of_subring_apply, coeff_restriction]
theorem
polynomial.map_restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "algebra.algebra_map_of_subring_apply", "algebra_map", "comm_ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
degree_restriction {p : R[X]} : (restriction p).degree = p.degree
by simp [degree]
theorem
polynomial.degree_restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_degree_restriction {p : R[X]} : (restriction p).nat_degree = p.nat_degree
by simp [nat_degree]
theorem
polynomial.nat_degree_restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monic_restriction {p : R[X]} : monic (restriction p) ↔ monic p
begin simp only [monic, leading_coeff, nat_degree_restriction], rw [←@coeff_restriction _ _ p], exact ⟨λ H, by { rw H, refl }, λ H, subtype.coe_injective H⟩ end
theorem
polynomial.monic_restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "subtype.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restriction_zero : restriction (0 : R[X]) = 0
by simp only [restriction, finset.sum_empty, support_zero]
theorem
polynomial.restriction_zero
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restriction_one : restriction (1 : R[X]) = 1
ext $ λ i, subtype.eq $ by rw [coeff_restriction', coeff_one, coeff_one]; split_ifs; refl
theorem
polynomial.restriction_one
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval₂_restriction {p : R[X]} : eval₂ f x p = eval₂ (f.comp (subring.subtype (subring.closure (p.frange : set R)))) x p.restriction
begin simp only [eval₂_eq_sum, sum, support_restriction, ←@coeff_restriction _ _ p], refl, end
theorem
polynomial.eval₂_restriction
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "subring.closure", "subring.subtype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_subring (hp : (↑p.frange : set R) ⊆ T) : T[X]
∑ i in p.support, monomial i (⟨p.coeff i, if H : p.coeff i = 0 then H.symm ▸ T.zero_mem else hp (p.coeff_mem_frange _ H)⟩ : T)
def
polynomial.to_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
Given a polynomial `p` and a subring `T` that contains the coefficients of `p`, return the corresponding polynomial whose coefficients are in `T`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_to_subring {n : ℕ} : ↑(coeff (to_subring p T hp) n) = coeff p n
begin simp only [to_subring, coeff_monomial, finset_sum_coeff, mem_support_iff, finset.sum_ite_eq', ne.def, ite_not], split_ifs, { rw h, refl }, { refl } end
theorem
polynomial.coeff_to_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ite_not" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_to_subring' {n : ℕ} : (coeff (to_subring p T hp) n).1 = coeff p n
coeff_to_subring _ _ hp
theorem
polynomial.coeff_to_subring'
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
support_to_subring : support (to_subring p T hp) = support p
begin ext i, simp only [mem_support_iff, not_iff_not, ne.def], conv_rhs { rw [← coeff_to_subring p T hp] }, exact ⟨λ H, by { rw H, refl }, λ H, subtype.coe_injective H⟩ end
lemma
polynomial.support_to_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "not_iff_not", "subtype.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
degree_to_subring : (to_subring p T hp).degree = p.degree
by simp [degree]
theorem
polynomial.degree_to_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_degree_to_subring : (to_subring p T hp).nat_degree = p.nat_degree
by simp [nat_degree]
theorem
polynomial.nat_degree_to_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
monic_to_subring : monic (to_subring p T hp) ↔ monic p
begin simp_rw [monic, leading_coeff, nat_degree_to_subring, ← coeff_to_subring p T hp], exact ⟨λ H, by { rw H, refl }, λ H, subtype.coe_injective H⟩ end
theorem
polynomial.monic_to_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "subtype.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_subring_zero : to_subring (0 : R[X]) T (by simp [frange_zero]) = 0
by { ext i, simp }
theorem
polynomial.to_subring_zero
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_subring_one : to_subring (1 : R[X]) T (set.subset.trans frange_one $finset.singleton_subset_set_iff.2 T.one_mem) = 1
ext $ λ i, subtype.eq $ by rw [coeff_to_subring', coeff_one, coeff_one]; split_ifs; refl
theorem
polynomial.to_subring_one
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "set.subset.trans" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_to_subring : (p.to_subring T hp).map (subring.subtype T) = p
by { ext n, simp [coeff_map] }
theorem
polynomial.map_to_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "subring.subtype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_subring (p : T[X]) : R[X]
∑ i in p.support, monomial i (p.coeff i : R)
def
polynomial.of_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
Given a polynomial whose coefficients are in some subring, return the corresponding polynomial whose coefficients are in the ambient ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_of_subring (p : T[X]) (n : ℕ) : coeff (of_subring T p) n = (coeff p n : T)
begin simp only [of_subring, coeff_monomial, finset_sum_coeff, mem_support_iff, finset.sum_ite_eq', ite_eq_right_iff, ne.def, ite_not, not_not, ite_eq_left_iff], assume h, rw h, refl end
lemma
polynomial.coeff_of_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ite_eq_left_iff", "ite_eq_right_iff", "ite_not", "not_not" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frange_of_subring {p : T[X]} : (↑(p.of_subring T).frange : set R) ⊆ T
begin assume i hi, simp only [frange, set.mem_image, mem_support_iff, ne.def, finset.mem_coe, finset.coe_image] at hi, rcases hi with ⟨n, hn, h'n⟩, rw [← h'n, coeff_of_subring], exact subtype.mem (coeff p n : T) end
theorem
polynomial.frange_of_subring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finset.coe_image", "finset.mem_coe", "set.mem_image", "subtype.mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_ker_mod_by_monic (hq : q.monic) {p : R[X]} : p ∈ (mod_by_monic_hom q).ker ↔ q ∣ p
linear_map.mem_ker.trans (dvd_iff_mod_by_monic_eq_zero hq)
lemma
polynomial.mem_ker_mod_by_monic
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ker_mod_by_monic_hom (hq : q.monic) : (polynomial.mod_by_monic_hom q).ker = (ideal.span {q}).restrict_scalars R
submodule.ext (λ f, (mem_ker_mod_by_monic hq).trans ideal.mem_span_singleton.symm)
lemma
polynomial.ker_mod_by_monic_hom
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal.span", "polynomial.mod_by_monic_hom", "restrict_scalars", "submodule.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_polynomial (I : ideal R[X]) : submodule R R[X]
{ carrier := I.carrier, zero_mem' := I.zero_mem, add_mem' := λ _ _, I.add_mem, smul_mem' := λ c x H, by { rw [← C_mul'], exact I.mul_mem_left _ H } }
def
ideal.of_polynomial
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal", "submodule" ]
Transport an ideal of `R[X]` to an `R`-submodule of `R[X]`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_of_polynomial (x) : x ∈ I.of_polynomial ↔ x ∈ I
iff.rfl
theorem
ideal.mem_of_polynomial
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
degree_le (n : with_bot ℕ) : submodule R R[X]
degree_le R n ⊓ I.of_polynomial
def
ideal.degree_le
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "submodule", "with_bot" ]
Given an ideal `I` of `R[X]`, make the `R`-submodule of `I` consisting of polynomials of degree ≤ `n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
leading_coeff_nth (n : ℕ) : ideal R
(I.degree_le n).map $ lcoeff R n
def
ideal.leading_coeff_nth
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal" ]
Given an ideal `I` of `R[X]`, make the ideal in `R` of leading coefficients of polynomials in `I` with degree ≤ `n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
leading_coeff : ideal R
⨆ n : ℕ, I.leading_coeff_nth n
def
ideal.leading_coeff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal" ]
Given an ideal `I` in `R[X]`, make the ideal in `R` of the leading coefficients in `I`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
polynomial_mem_ideal_of_coeff_mem_ideal (I : ideal R[X]) (p : R[X]) (hp : ∀ (n : ℕ), (p.coeff n) ∈ I.comap (C : R →+* R[X])) : p ∈ I
sum_C_mul_X_pow_eq p ▸ submodule.sum_mem I (λ n hn, I.mul_mem_right _ (hp n))
lemma
ideal.polynomial_mem_ideal_of_coeff_mem_ideal
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal", "submodule.sum_mem" ]
If every coefficient of a polynomial is in an ideal `I`, then so is the polynomial itself
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_map_C_iff {I : ideal R} {f : R[X]} : f ∈ (ideal.map (C : R →+* R[X]) I : ideal R[X]) ↔ ∀ n : ℕ, f.coeff n ∈ I
begin split, { intros hf, apply submodule.span_induction hf, { intros f hf n, cases (set.mem_image _ _ _).mp hf with x hx, rw [← hx.right, coeff_C], by_cases (n = 0), { simpa [h] using hx.left }, { simp [h] } }, { simp }, { exact λ f g hf hg n, by simp [I.add_mem (hf n)...
theorem
ideal.mem_map_C_iff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal", "ideal.map", "mul_comm", "set.mem_image", "smul_eq_mul", "submodule.span_induction" ]
The push-forward of an ideal `I` of `R` to `R[X]` via inclusion is exactly the set of polynomials whose coefficients are in `I`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.polynomial.ker_map_ring_hom (f : R →+* S) : (polynomial.map_ring_hom f).ker = f.ker.map (C : R →+* R[X])
begin ext, rw [mem_map_C_iff, ring_hom.mem_ker, polynomial.ext_iff], simp_rw [coe_map_ring_hom, coeff_map, coeff_zero, ring_hom.mem_ker], end
lemma
polynomial.ker_map_ring_hom
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "polynomial.ext_iff", "polynomial.map_ring_hom", "ring_hom.mem_ker" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_leading_coeff_nth (n : ℕ) (x) : x ∈ I.leading_coeff_nth n ↔ ∃ p ∈ I, degree p ≤ n ∧ p.leading_coeff = x
begin simp only [leading_coeff_nth, degree_le, submodule.mem_map, lcoeff_apply, submodule.mem_inf, mem_degree_le], split, { rintro ⟨p, ⟨hpdeg, hpI⟩, rfl⟩, cases lt_or_eq_of_le hpdeg with hpdeg hpdeg, { refine ⟨0, I.zero_mem, bot_le, _⟩, rw [leading_coeff_zero, eq_comm], exact coeff_eq_zero...
theorem
ideal.mem_leading_coeff_nth
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "add_tsub_cancel_of_le", "bot_le", "le_rfl", "polynomial.leading_coeff", "submodule.mem_inf", "submodule.mem_map", "with_bot.coe_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_leading_coeff_nth_zero (x) : x ∈ I.leading_coeff_nth 0 ↔ C x ∈ I
(mem_leading_coeff_nth _ _ _).trans ⟨λ ⟨p, hpI, hpdeg, hpx⟩, by rwa [← hpx, polynomial.leading_coeff, nat.eq_zero_of_le_zero (nat_degree_le_of_degree_le hpdeg), ← eq_C_of_degree_le_zero hpdeg], λ hx, ⟨C x, hx, degree_C_le, leading_coeff_C x⟩⟩
theorem
ideal.mem_leading_coeff_nth_zero
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "polynomial.leading_coeff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
leading_coeff_nth_mono {m n : ℕ} (H : m ≤ n) : I.leading_coeff_nth m ≤ I.leading_coeff_nth n
begin intros r hr, simp only [set_like.mem_coe, mem_leading_coeff_nth] at hr ⊢, rcases hr with ⟨p, hpI, hpdeg, rfl⟩, refine ⟨p * X ^ (n - m), I.mul_mem_right _ hpI, _, leading_coeff_mul_X_pow⟩, refine le_trans (degree_mul_le _ _) _, refine le_trans (add_le_add hpdeg (degree_X_pow_le _)) _, rw [← with_bot....
theorem
ideal.leading_coeff_nth_mono
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "add_tsub_cancel_of_le", "le_rfl", "set_like.mem_coe", "with_bot.coe_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_leading_coeff (x) : x ∈ I.leading_coeff ↔ ∃ p ∈ I, polynomial.leading_coeff p = x
begin rw [leading_coeff, submodule.mem_supr_of_directed], simp only [mem_leading_coeff_nth], { split, { rintro ⟨i, p, hpI, hpdeg, rfl⟩, exact ⟨p, hpI, rfl⟩ }, rintro ⟨p, hpI, rfl⟩, exact ⟨nat_degree p, p, hpI, degree_le_nat_degree, rfl⟩ }, intros i j, exact ⟨i + j, I.leading_coeff_nth_mono (nat.le_add_right...
theorem
ideal.mem_leading_coeff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "polynomial.leading_coeff", "submodule.mem_supr_of_directed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.polynomial.coeff_prod_mem_ideal_pow_tsub {ι : Type*} (s : finset ι) (f : ι → R[X]) (I : ideal R) (n : ι → ℕ) (h : ∀ (i ∈ s) k, (f i).coeff k ∈ I ^ (n i - k)) (k : ℕ) : (s.prod f).coeff k ∈ I ^ (s.sum n - k)
begin classical, induction s using finset.induction with a s ha hs generalizing k, { rw [sum_empty, prod_empty, coeff_one, zero_tsub, pow_zero, ideal.one_eq_top], exact submodule.mem_top }, { rw [sum_insert ha, prod_insert ha, coeff_mul], apply sum_mem, rintro ⟨i, j⟩ e, obtain rfl : i + j = k :=...
lemma
polynomial.coeff_prod_mem_ideal_pow_tsub
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "add_tsub_add_le_tsub_add_tsub", "finset", "finset.induction", "ideal", "ideal.mul_mem_mul", "ideal.one_eq_top", "ideal.pow_le_pow", "pow_add", "pow_zero", "submodule.mem_top", "zero_tsub" ]
If `I` is an ideal, and `pᵢ` is a finite family of polynomials each satisfying `∀ k, (pᵢ)ₖ ∈ Iⁿⁱ⁻ᵏ` for some `nᵢ`, then `p = ∏ pᵢ` also satisfies `∀ k, pₖ ∈ Iⁿ⁻ᵏ` with `n = ∑ nᵢ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
polynomial_not_is_field : ¬ is_field R[X]
begin nontriviality R, intro hR, obtain ⟨p, hp⟩ := hR.mul_inv_cancel X_ne_zero, have hp0 : p ≠ 0, { rintro rfl, rw [mul_zero] at hp, exact zero_ne_one hp }, have := degree_lt_degree_mul_X hp0, rw [←X_mul, congr_arg degree hp, degree_one, nat.with_bot.lt_zero_iff, degree_eq_bot] at this, exact hp...
lemma
ideal.polynomial_not_is_field
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "is_field", "mul_zero", "nat.with_bot.lt_zero_iff", "zero_ne_one" ]
`R[X]` is never a field for any ring `R`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_zero_of_constant_mem_of_maximal (hR : is_field R) (I : ideal R[X]) [hI : I.is_maximal] (x : R) (hx : C x ∈ I) : x = 0
begin refine classical.by_contradiction (λ hx0, hI.ne_top ((eq_top_iff_one I).2 _)), obtain ⟨y, hy⟩ := hR.mul_inv_cancel hx0, convert I.mul_mem_left (C y) hx, rw [← C.map_mul, hR.mul_comm y x, hy, ring_hom.map_one], end
lemma
ideal.eq_zero_of_constant_mem_of_maximal
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal", "is_field", "ring_hom.map_one" ]
The only constant in a maximal ideal over a field is `0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_prime_map_C_iff_is_prime (P : ideal R) : is_prime (map (C : R →+* R[X]) P : ideal R[X]) ↔ is_prime P
begin -- Porting note: the following proof avoids quotient rings -- It can be golfed substantially by using something like -- `(quotient.is_domain_iff_prime (map C P : ideal R[X]))` split, { intro H, have := @comap_is_prime R R[X] (R →+* R[X]) _ _ _ C (map C P) H, convert this using 1, ext x, ...
lemma
ideal.is_prime_map_C_iff_is_prime
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finset.insert_erase", "finset.mem_erase", "finset.nat.mem_antidiagonal", "finset.not_mem_erase", "ideal", "mul_comm", "not_and_distrib", "not_forall", "not_or_distrib", "or_iff_not_imp_left", "prod.mk.inj_iff", "submodule.zero_mem" ]
If `P` is a prime ideal of `R`, then `P.R[x]` is a prime ideal of `R[x]`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_prime_map_C_of_is_prime {P : ideal R} (H : is_prime P) : is_prime (map (C : R →+* R[X]) P : ideal R[X])
(is_prime_map_C_iff_is_prime P).mpr H
lemma
ideal.is_prime_map_C_of_is_prime
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal" ]
If `P` is a prime ideal of `R`, then `P.R[x]` is a prime ideal of `R[x]`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_fg_degree_le [is_noetherian_ring R] (I : ideal R[X]) (n : ℕ) : submodule.fg (I.degree_le n)
is_noetherian_submodule_left.1 (is_noetherian_of_fg_of_noetherian _ ⟨_, degree_le_eq_span_X_pow.symm⟩) _
theorem
ideal.is_fg_degree_le
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal", "is_noetherian_of_fg_of_noetherian", "is_noetherian_ring", "submodule.fg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prime_C_iff : prime (C r) ↔ prime r
⟨ comap_prime C (eval_ring_hom (0 : R)) (λ r, eval_C), λ hr, by { have := hr.1, rw ← ideal.span_singleton_prime at hr ⊢, { convert ideal.is_prime_map_C_of_is_prime hr using 1, rw [ideal.map_span, set.image_singleton] }, exacts [λ h, this (C_eq_zero.1 h), this] } ⟩
lemma
polynomial.prime_C_iff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "comap_prime", "ideal.is_prime_map_C_of_is_prime", "ideal.map_span", "ideal.span_singleton_prime", "prime", "set.image_singleton" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prime_C_iff_of_fintype [fintype σ] : prime (C r : mv_polynomial σ R) ↔ prime r
begin rw (rename_equiv R (fintype.equiv_fin σ)).to_mul_equiv.prime_iff, convert_to prime (C r) ↔ _, { congr, apply rename_C }, { symmetry, induction fintype.card σ with d hd, { exact (is_empty_alg_equiv R (fin 0)).to_mul_equiv.symm.prime_iff }, { rw [hd, ← polynomial.prime_C_iff], convert (fin_succ_...
lemma
mv_polynomial.prime_C_iff_of_fintype
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "fin_succ_equiv", "fintype", "fintype.card", "fintype.equiv_fin", "mv_polynomial", "polynomial.prime_C_iff", "prime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prime_C_iff : prime (C r : mv_polynomial σ R) ↔ prime r
⟨ comap_prime C constant_coeff (constant_coeff_C _), λ hr, ⟨ λ h, hr.1 $ by { rw [← C_inj, h], simp }, λ h, hr.2.1 $ by { rw ← constant_coeff_C _ r, exact h.map _ }, λ a b hd, begin obtain ⟨s,a',b',rfl,rfl⟩ := exists_finset_rename₂ a b, rw ← algebra_map_eq at hd, have : algebra_map R _ r ∣ a' * b'...
lemma
mv_polynomial.prime_C_iff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "algebra_map", "comap_prime", "mv_polynomial", "prime", "subtype.coe_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prime_rename_iff (s : set σ) {p : mv_polynomial s R} : prime (rename (coe : s → σ) p) ↔ prime p
begin classical, symmetry, let eqv := (sum_alg_equiv R _ _).symm.trans (rename_equiv R $ (equiv.sum_comm ↥sᶜ s).trans $ equiv.set.sum_compl s), rw [← prime_C_iff ↥sᶜ, eqv.to_mul_equiv.prime_iff], convert iff.rfl, suffices : (rename coe).to_ring_hom = eqv.to_alg_hom.to_ring_hom.comp C, { apply ring_hom.congr...
lemma
mv_polynomial.prime_rename_iff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "equiv.set.sum_compl", "equiv.sum_comm", "mv_polynomial", "prime", "ring_hom.congr_fun", "ring_hom_ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
polynomial.is_noetherian_ring [is_noetherian_ring R] : is_noetherian_ring R[X]
is_noetherian_ring_iff.2 ⟨assume I : ideal R[X], let M := well_founded.min (is_noetherian_iff_well_founded.1 (by apply_instance)) (set.range I.leading_coeff_nth) ⟨_, ⟨0, rfl⟩⟩ in have hm : M ∈ set.range I.leading_coeff_nth := well_founded.min_mem _ _ _, let ⟨N, HN⟩ := hm, ⟨s, hs⟩ := I.is_fg_degree_le N in have hm2 : ...
theorem
polynomial.is_noetherian_ring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "add_tsub_cancel_of_le", "ideal", "ideal.add_mem", "ideal.mul_mem_left", "ideal.span", "ideal.subset_span", "ideal.zero_mem", "ih", "is_noetherian_ring", "mul_one", "mul_zero", "nontrivial", "polynomial.X", "polynomial.degree_X_pow", "polynomial.degree_eq_nat_degree", "polynomial.degre...
Hilbert basis theorem: a polynomial ring over a noetherian ring is a noetherian ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_irreducible_of_degree_pos {R : Type u} [comm_ring R] [is_domain R] [wf_dvd_monoid R] {f : R[X]} (hf : 0 < f.degree) : ∃ g, irreducible g ∧ g ∣ f
wf_dvd_monoid.exists_irreducible_factor (λ huf, ne_of_gt hf $ degree_eq_zero_of_is_unit huf) (λ hf0, not_lt_of_lt hf $ hf0.symm ▸ (@degree_zero R _).symm ▸ with_bot.bot_lt_coe _)
theorem
polynomial.exists_irreducible_of_degree_pos
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "comm_ring", "irreducible", "is_domain", "wf_dvd_monoid", "wf_dvd_monoid.exists_irreducible_factor", "with_bot.bot_lt_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_irreducible_of_nat_degree_pos {R : Type u} [comm_ring R] [is_domain R] [wf_dvd_monoid R] {f : R[X]} (hf : 0 < f.nat_degree) : ∃ g, irreducible g ∧ g ∣ f
exists_irreducible_of_degree_pos $ by { contrapose! hf, exact nat_degree_le_of_degree_le hf }
theorem
polynomial.exists_irreducible_of_nat_degree_pos
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "comm_ring", "irreducible", "is_domain", "wf_dvd_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_irreducible_of_nat_degree_ne_zero {R : Type u} [comm_ring R] [is_domain R] [wf_dvd_monoid R] {f : R[X]} (hf : f.nat_degree ≠ 0) : ∃ g, irreducible g ∧ g ∣ f
exists_irreducible_of_nat_degree_pos $ nat.pos_of_ne_zero hf
theorem
polynomial.exists_irreducible_of_nat_degree_ne_zero
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "comm_ring", "irreducible", "is_domain", "wf_dvd_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
linear_independent_powers_iff_aeval (f : M →ₗ[R] M) (v : M) : linear_independent R (λ n : ℕ, (f ^ n) v) ↔ ∀ (p : R[X]), aeval f p v = 0 → p = 0
begin rw linear_independent_iff, simp only [finsupp.total_apply, aeval_endomorphism, forall_iff_forall_finsupp, sum, support, coeff, of_finsupp_eq_zero], exact iff.rfl, end
lemma
polynomial.linear_independent_powers_iff_aeval
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finsupp.total_apply", "linear_independent", "linear_independent_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
disjoint_ker_aeval_of_coprime (f : M →ₗ[R] M) {p q : R[X]} (hpq : is_coprime p q) : disjoint (aeval f p).ker (aeval f q).ker
begin rw disjoint_iff_inf_le, intros v hv, rcases hpq with ⟨p', q', hpq'⟩, simpa [linear_map.mem_ker.1 (submodule.mem_inf.1 hv).1, linear_map.mem_ker.1 (submodule.mem_inf.1 hv).2] using congr_arg (λ p : R[X], aeval f p v) hpq'.symm, end
lemma
polynomial.disjoint_ker_aeval_of_coprime
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "disjoint", "disjoint_iff_inf_le", "is_coprime" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sup_aeval_range_eq_top_of_coprime (f : M →ₗ[R] M) {p q : R[X]} (hpq : is_coprime p q) : (aeval f p).range ⊔ (aeval f q).range = ⊤
begin rw eq_top_iff, intros v hv, rw submodule.mem_sup, rcases hpq with ⟨p', q', hpq'⟩, use aeval f (p * p') v, use linear_map.mem_range.2 ⟨aeval f p' v, by simp only [linear_map.mul_apply, aeval_mul]⟩, use aeval f (q * q') v, use linear_map.mem_range.2 ⟨aeval f q' v, by simp only [linear_map.mul_apply,...
lemma
polynomial.sup_aeval_range_eq_top_of_coprime
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "eq_top_iff", "is_coprime", "linear_map.mul_apply", "mul_comm", "submodule.mem_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sup_ker_aeval_le_ker_aeval_mul {f : M →ₗ[R] M} {p q : R[X]} : (aeval f p).ker ⊔ (aeval f q).ker ≤ (aeval f (p * q)).ker
begin intros v hv, rcases submodule.mem_sup.1 hv with ⟨x, hx, y, hy, hxy⟩, have h_eval_x : aeval f (p * q) x = 0, { rw [mul_comm, aeval_mul, linear_map.mul_apply, linear_map.mem_ker.1 hx, linear_map.map_zero] }, have h_eval_y : aeval f (p * q) y = 0, { rw [aeval_mul, linear_map.mul_apply, linear_map.mem_ker...
lemma
polynomial.sup_ker_aeval_le_ker_aeval_mul
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "linear_map.map_add", "linear_map.map_zero", "linear_map.mem_ker", "linear_map.mul_apply", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sup_ker_aeval_eq_ker_aeval_mul_of_coprime (f : M →ₗ[R] M) {p q : R[X]} (hpq : is_coprime p q) : (aeval f p).ker ⊔ (aeval f q).ker = (aeval f (p * q)).ker
begin apply le_antisymm sup_ker_aeval_le_ker_aeval_mul, intros v hv, rw submodule.mem_sup, rcases hpq with ⟨p', q', hpq'⟩, have h_eval₂_qpp' := calc aeval f (q * (p * p')) v = aeval f (p' * (p * q)) v : by rw [mul_comm, mul_assoc, mul_comm, mul_assoc, mul_comm q p] ... = 0 : by rw [aeval_m...
lemma
polynomial.sup_ker_aeval_eq_ker_aeval_mul_of_coprime
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "is_coprime", "linear_map.map_zero", "linear_map.mul_apply", "map_mul", "mul_assoc", "mul_comm", "submodule.mem_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_noetherian_ring_fin_0 [is_noetherian_ring R] : is_noetherian_ring (mv_polynomial (fin 0) R)
is_noetherian_ring_of_ring_equiv R ((mv_polynomial.is_empty_ring_equiv R pempty).symm.trans (rename_equiv R fin_zero_equiv'.symm).to_ring_equiv)
lemma
mv_polynomial.is_noetherian_ring_fin_0
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "is_noetherian_ring", "is_noetherian_ring_of_ring_equiv", "mv_polynomial", "mv_polynomial.is_empty_ring_equiv", "pempty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_noetherian_ring_fin [is_noetherian_ring R] : ∀ {n : ℕ}, is_noetherian_ring (mv_polynomial (fin n) R)
| 0 := is_noetherian_ring_fin_0 | (n+1) := @is_noetherian_ring_of_ring_equiv (polynomial (mv_polynomial (fin n) R)) _ _ _ (mv_polynomial.fin_succ_equiv _ n).to_ring_equiv.symm (@polynomial.is_noetherian_ring (mv_polynomial (fin n) R) _ (is_noetherian_ring_fin))
theorem
mv_polynomial.is_noetherian_ring_fin
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "is_noetherian_ring", "is_noetherian_ring_of_ring_equiv", "mv_polynomial", "mv_polynomial.fin_succ_equiv", "polynomial", "polynomial.is_noetherian_ring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_noetherian_ring [finite σ] [is_noetherian_ring R] : is_noetherian_ring (mv_polynomial σ R)
by casesI nonempty_fintype σ; exact @is_noetherian_ring_of_ring_equiv (mv_polynomial (fin (fintype.card σ)) R) _ _ _ (rename_equiv R (fintype.equiv_fin σ).symm).to_ring_equiv is_noetherian_ring_fin
instance
mv_polynomial.is_noetherian_ring
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "finite", "fintype.card", "fintype.equiv_fin", "is_noetherian_ring", "is_noetherian_ring_of_ring_equiv", "mv_polynomial", "nonempty_fintype" ]
The multivariate polynomial ring in finitely many variables over a noetherian ring is itself a noetherian ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
no_zero_divisors_fin (R : Type u) [comm_semiring R] [no_zero_divisors R] : ∀ (n : ℕ), no_zero_divisors (mv_polynomial (fin n) R)
| 0 := (mv_polynomial.is_empty_alg_equiv R _).injective.no_zero_divisors _ (map_zero _) (map_mul _) | (n+1) := begin haveI := no_zero_divisors_fin n, exact (mv_polynomial.fin_succ_equiv R n).injective.no_zero_divisors _ (map_zero _) (map_mul _) end
lemma
mv_polynomial.no_zero_divisors_fin
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "comm_semiring", "map_mul", "mv_polynomial", "mv_polynomial.fin_succ_equiv", "mv_polynomial.is_empty_alg_equiv", "no_zero_divisors" ]
Auxiliary lemma: Multivariate polynomials over an integral domain with variables indexed by `fin n` form an integral domain. This fact is proven inductively, and then used to prove the general case without any finiteness hypotheses. See `mv_polynomial.no_zero_divisors` for the general case.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
no_zero_divisors_of_finite (R : Type u) (σ : Type v) [comm_semiring R] [finite σ] [no_zero_divisors R] : no_zero_divisors (mv_polynomial σ R)
begin casesI nonempty_fintype σ, haveI := no_zero_divisors_fin R (fintype.card σ), exact (rename_equiv R (fintype.equiv_fin σ)).injective.no_zero_divisors _ (map_zero _) (map_mul _) end
lemma
mv_polynomial.no_zero_divisors_of_finite
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "comm_semiring", "finite", "fintype.card", "fintype.equiv_fin", "map_mul", "mv_polynomial", "no_zero_divisors", "nonempty_fintype" ]
Auxiliary definition: Multivariate polynomials in finitely many variables over an integral domain form an integral domain. This fact is proven by transport of structure from the `mv_polynomial.no_zero_divisors_fin`, and then used to prove the general case without finiteness hypotheses. See `mv_polynomial.no_zero_diviso...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mv_polynomial_eq_eval₂ {S : Type*} [comm_ring S] [finite σ] (ϕ : mv_polynomial σ R →+* S) (p : mv_polynomial σ R) : ϕ p = mv_polynomial.eval₂ (ϕ.comp mv_polynomial.C) (λ s, ϕ (mv_polynomial.X s)) p
begin casesI nonempty_fintype σ, refine trans (congr_arg ϕ (mv_polynomial.as_sum p)) _, rw [mv_polynomial.eval₂_eq', ϕ.map_sum], congr, ext, simp only [monomial_eq, ϕ.map_pow, ϕ.map_prod, ϕ.comp_apply, ϕ.map_mul, finsupp.prod_pow], end
lemma
mv_polynomial.map_mv_polynomial_eq_eval₂
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "comm_ring", "finite", "finsupp.prod_pow", "mv_polynomial", "mv_polynomial.C", "mv_polynomial.X", "mv_polynomial.as_sum", "mv_polynomial.eval₂", "mv_polynomial.eval₂_eq'", "nonempty_fintype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_ideal_of_coeff_mem_ideal (I : ideal (mv_polynomial σ R)) (p : mv_polynomial σ R) (hcoe : ∀ (m : σ →₀ ℕ), p.coeff m ∈ I.comap (C : R →+* mv_polynomial σ R)) : p ∈ I
begin rw as_sum p, suffices : ∀ m ∈ p.support, monomial m (mv_polynomial.coeff m p) ∈ I, { exact submodule.sum_mem I this }, intros m hm, rw [← mul_one (coeff m p), ← C_mul_monomial], suffices : C (coeff m p) ∈ I, { exact I.mul_mem_right (monomial m 1) this }, simpa [ideal.mem_comap] using hcoe m end
lemma
mv_polynomial.mem_ideal_of_coeff_mem_ideal
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal", "ideal.mem_comap", "mul_one", "mv_polynomial", "mv_polynomial.coeff", "submodule.sum_mem" ]
If every coefficient of a polynomial is in an ideal `I`, then so is the polynomial itself, multivariate version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_map_C_iff {I : ideal R} {f : mv_polynomial σ R} : f ∈ (ideal.map (C : R →+* mv_polynomial σ R) I : ideal (mv_polynomial σ R)) ↔ ∀ (m : σ →₀ ℕ), f.coeff m ∈ I
begin split, { intros hf, apply submodule.span_induction hf, { intros f hf n, cases (set.mem_image _ _ _).mp hf with x hx, rw [← hx.right, coeff_C], by_cases (n = 0), { simpa [h] using hx.left }, { simp [ne.symm h] } }, { simp }, { exact λ f g hf hg n, by simp [I.add_me...
theorem
mv_polynomial.mem_map_C_iff
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "ideal", "ideal.map", "ideal.mem_map_of_mem", "ideal.mul_mem_right", "mul_one", "mv_polynomial", "set.mem_image", "smul_eq_mul", "submodule.span_induction", "submodule.sum_mem" ]
The push-forward of an ideal `I` of `R` to `mv_polynomial σ R` via inclusion is exactly the set of polynomials whose coefficients are in `I`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ker_map (f : R →+* S) : (map f : mv_polynomial σ R →+* mv_polynomial σ S).ker = f.ker.map (C : R →+* mv_polynomial σ R)
begin ext, rw [mv_polynomial.mem_map_C_iff, ring_hom.mem_ker, mv_polynomial.ext_iff], simp_rw [coeff_map, coeff_zero, ring_hom.mem_ker], end
lemma
mv_polynomial.ker_map
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "mv_polynomial", "mv_polynomial.ext_iff", "mv_polynomial.mem_map_C_iff", "ring_hom.mem_ker" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_factorization_monoid : unique_factorization_monoid D[X]
begin haveI := arbitrary (normalization_monoid D), haveI := to_normalized_gcd_monoid D, exact ufm_of_gcd_of_wf_dvd_monoid end
instance
polynomial.unique_factorization_monoid
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "normalization_monoid", "ufm_of_gcd_of_wf_dvd_monoid", "unique_factorization_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_factorization_monoid_of_fintype [fintype σ] : unique_factorization_monoid (mv_polynomial σ D)
(rename_equiv D (fintype.equiv_fin σ)).to_mul_equiv.symm.unique_factorization_monoid $ begin induction fintype.card σ with d hd, { apply (is_empty_alg_equiv D (fin 0)).to_mul_equiv.symm.unique_factorization_monoid, apply_instance }, { apply (fin_succ_equiv D d).to_mul_equiv.symm.unique_factorization_monoid, ...
lemma
mv_polynomial.unique_factorization_monoid_of_fintype
ring_theory.polynomial
src/ring_theory/polynomial/basic.lean
[ "algebra.char_p.basic", "algebra.geom_sum", "data.mv_polynomial.comm_ring", "data.mv_polynomial.equiv", "ring_theory.polynomial.content", "ring_theory.unique_factorization_domain" ]
[ "fin_succ_equiv", "fintype", "fintype.card", "fintype.equiv_fin", "mv_polynomial", "polynomial.unique_factorization_monoid", "unique_factorization_monoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bernstein_polynomial (n ν : ℕ) : R[X]
choose n ν * X^ν * (1 - X)^(n - ν)
def
bernstein_polynomial
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[]
`bernstein_polynomial R n ν` is `(choose n ν) * X^ν * (1 - X)^(n - ν)`. Although the coefficients are integers, it is convenient to work over an arbitrary commutative ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_zero_of_lt {n ν : ℕ} (h : n < ν) : bernstein_polynomial R n ν = 0
by simp [bernstein_polynomial, nat.choose_eq_zero_of_lt h]
lemma
bernstein_polynomial.eq_zero_of_lt
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "nat.choose_eq_zero_of_lt" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map (f : R →+* S) (n ν : ℕ) : (bernstein_polynomial R n ν).map f = bernstein_polynomial S n ν
by simp [bernstein_polynomial]
lemma
bernstein_polynomial.map
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
flip (n ν : ℕ) (h : ν ≤ n) : (bernstein_polynomial R n ν).comp (1-X) = bernstein_polynomial R n (n-ν)
by simp [bernstein_polynomial, h, tsub_tsub_assoc, mul_right_comm]
lemma
bernstein_polynomial.flip
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "mul_right_comm", "tsub_tsub_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
flip' (n ν : ℕ) (h : ν ≤ n) : bernstein_polynomial R n ν = (bernstein_polynomial R n (n-ν)).comp (1-X)
by simp [←flip _ _ _ h, polynomial.comp_assoc]
lemma
bernstein_polynomial.flip'
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "polynomial.comp_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval_at_0 (n ν : ℕ) : (bernstein_polynomial R n ν).eval 0 = if ν = 0 then 1 else 0
begin rw [bernstein_polynomial], split_ifs, { subst h, simp, }, { simp [zero_pow (nat.pos_of_ne_zero h)], }, end
lemma
bernstein_polynomial.eval_at_0
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "zero_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval_at_1 (n ν : ℕ) : (bernstein_polynomial R n ν).eval 1 = if ν = n then 1 else 0
begin rw [bernstein_polynomial], split_ifs, { subst h, simp, }, { obtain w | w := (n - ν).eq_zero_or_pos, { simp [nat.choose_eq_zero_of_lt ((tsub_eq_zero_iff_le.mp w).lt_of_ne (ne.symm h))] }, { simp [zero_pow w] } }, end.
lemma
bernstein_polynomial.eval_at_1
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "nat.choose_eq_zero_of_lt", "zero_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
derivative_succ_aux (n ν : ℕ) : (bernstein_polynomial R (n+1) (ν+1)).derivative = (n+1) * (bernstein_polynomial R n ν - bernstein_polynomial R n (ν + 1))
begin rw [bernstein_polynomial], suffices : ↑((n + 1).choose (ν + 1)) * (↑(ν + 1) * X ^ ν) * (1 - X) ^ (n - ν) -(↑((n + 1).choose (ν + 1)) * X ^ (ν + 1) * (↑(n - ν) * (1 - X) ^ (n - ν - 1))) = ↑(n + 1) * (↑(n.choose ν) * X ^ ν * (1 - X) ^ (n - ν) - ↑(n.choose (ν + 1)) * X ^ (ν + 1) * (1 - X) ...
lemma
bernstein_polynomial.derivative_succ_aux
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "algebra_map.coe_one", "bernstein_polynomial", "mul_assoc", "mul_comm", "mul_neg", "mul_one", "nat.cast_add", "nat.cast_succ", "nat.choose_mul_succ_eq", "nat.succ_mul_choose_eq", "polynomial.C_eq_nat_cast", "polynomial.derivative_X", "polynomial.derivative_mul", "polynomial.derivative_nat_...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
derivative_succ (n ν : ℕ) : (bernstein_polynomial R n (ν+1)).derivative = n * (bernstein_polynomial R (n-1) ν - bernstein_polynomial R (n-1) (ν+1))
begin cases n, { simp [bernstein_polynomial], }, { rw nat.cast_succ, apply derivative_succ_aux, } end
lemma
bernstein_polynomial.derivative_succ
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "nat.cast_succ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
derivative_zero (n : ℕ) : (bernstein_polynomial R n 0).derivative = -n * bernstein_polynomial R (n-1) 0
by simp [bernstein_polynomial, polynomial.derivative_pow]
lemma
bernstein_polynomial.derivative_zero
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "polynomial.derivative_pow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterate_derivative_at_0_eq_zero_of_lt (n : ℕ) {ν k : ℕ} : k < ν → (polynomial.derivative^[k] (bernstein_polynomial R n ν)).eval 0 = 0
begin cases ν, { rintro ⟨⟩, }, { rw nat.lt_succ_iff, induction k with k ih generalizing n ν, { simp [eval_at_0], }, { simp only [derivative_succ, int.coe_nat_eq_zero, mul_eq_zero, function.comp_app, function.iterate_succ, polynomial.iterate_derivative_sub, polynomial.iterate_derivative...
lemma
bernstein_polynomial.iterate_derivative_at_0_eq_zero_of_lt
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "function.iterate_succ", "ih", "int.coe_nat_eq_zero", "mul_eq_zero", "mul_eq_zero_of_right", "nat.lt_succ_iff", "polynomial.derivative", "polynomial.eval_mul", "polynomial.eval_nat_cast", "polynomial.eval_sub", "polynomial.iterate_derivative_nat_cast_mul", "polynomial...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterate_derivative_succ_at_0_eq_zero (n ν : ℕ) : (polynomial.derivative^[ν] (bernstein_polynomial R n (ν+1))).eval 0 = 0
iterate_derivative_at_0_eq_zero_of_lt R n (lt_add_one ν)
lemma
bernstein_polynomial.iterate_derivative_succ_at_0_eq_zero
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "lt_add_one", "polynomial.derivative" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterate_derivative_at_0 (n ν : ℕ) : (polynomial.derivative^[ν] (bernstein_polynomial R n ν)).eval 0 = (pochhammer R ν).eval (n - (ν - 1) : ℕ)
begin by_cases h : ν ≤ n, { induction ν with ν ih generalizing n h, { simp [eval_at_0], }, { have h' : ν ≤ n-1 := le_tsub_of_add_le_right h, simp only [derivative_succ, ih (n-1) h', iterate_derivative_succ_at_0_eq_zero, nat.succ_sub_succ_eq_sub, tsub_zero, sub_zero, iterate_derivative_...
lemma
bernstein_polynomial.iterate_derivative_at_0
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "function.iterate_succ", "ih", "le_tsub_of_add_le_right", "nat.le_pred_of_lt", "pochhammer", "pochhammer_eval_succ", "pochhammer_succ_left", "polynomial.derivative", "pos_of_gt", "tsub_add_cancel_of_le", "tsub_add_eq_tsub_tsub", "tsub_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterate_derivative_at_0_ne_zero [char_zero R] (n ν : ℕ) (h : ν ≤ n) : (polynomial.derivative^[ν] (bernstein_polynomial R n ν)).eval 0 ≠ 0
begin simp only [int.coe_nat_eq_zero, bernstein_polynomial.iterate_derivative_at_0, ne.def, nat.cast_eq_zero], simp only [←pochhammer_eval_cast], norm_cast, apply ne_of_gt, obtain rfl|h' := nat.eq_zero_or_pos ν, { simp, }, { rw ← nat.succ_pred_eq_of_pos h' at h, exact pochhammer_pos _ _ (tsub_pos_...
lemma
bernstein_polynomial.iterate_derivative_at_0_ne_zero
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "bernstein_polynomial.iterate_derivative_at_0", "char_zero", "int.coe_nat_eq_zero", "nat.cast_eq_zero", "pochhammer_pos", "polynomial.derivative", "tsub_pos_of_lt" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterate_derivative_at_1_eq_zero_of_lt (n : ℕ) {ν k : ℕ} : k < n - ν → (polynomial.derivative^[k] (bernstein_polynomial R n ν)).eval 1 = 0
begin intro w, rw flip' _ _ _ (tsub_pos_iff_lt.mp (pos_of_gt w)).le, simp [polynomial.eval_comp, iterate_derivative_at_0_eq_zero_of_lt R n w], end
lemma
bernstein_polynomial.iterate_derivative_at_1_eq_zero_of_lt
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "polynomial.derivative", "polynomial.eval_comp", "pos_of_gt" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iterate_derivative_at_1 (n ν : ℕ) (h : ν ≤ n) : (polynomial.derivative^[n-ν] (bernstein_polynomial R n ν)).eval 1 = (-1)^(n-ν) * (pochhammer R (n - ν)).eval (ν + 1)
begin rw flip' _ _ _ h, simp [polynomial.eval_comp, h], obtain rfl | h' := h.eq_or_lt, { simp, }, { congr, norm_cast, rw [← tsub_add_eq_tsub_tsub, tsub_tsub_cancel_of_le (nat.succ_le_iff.mpr h')] }, end
lemma
bernstein_polynomial.iterate_derivative_at_1
ring_theory.polynomial
src/ring_theory/polynomial/bernstein.lean
[ "data.polynomial.derivative", "data.nat.choose.sum", "ring_theory.polynomial.pochhammer", "data.polynomial.algebra_map", "linear_algebra.linear_independent", "data.mv_polynomial.pderiv" ]
[ "bernstein_polynomial", "pochhammer", "polynomial.derivative", "polynomial.eval_comp", "tsub_add_eq_tsub_tsub", "tsub_tsub_cancel_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83