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coeff_zero_X_mul (φ : power_series R) : coeff R 0 (X * φ) = 0
by simp
lemma
power_series.coeff_zero_X_mul
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_C_mul_X_pow (x : R) (k n : ℕ) : coeff R n (C R x * X ^ k : power_series R) = if n = k then x else 0
by simp [X_pow_eq, coeff_monomial]
lemma
power_series.coeff_C_mul_X_pow
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_mul_X_pow (p : power_series R) (n d : ℕ) : coeff R (d + n) (p * X ^ n) = coeff R d p
begin rw [coeff_mul, finset.sum_eq_single (d, n), coeff_X_pow, if_pos rfl, mul_one], { rintros ⟨i,j⟩ h1 h2, rw [coeff_X_pow, if_neg, mul_zero], rintro rfl, apply h2, rw [finset.nat.mem_antidiagonal, add_right_cancel_iff] at h1, subst h1 }, { exact λ h1, (h1 (finset.nat.mem_antidiagonal.2 rfl)).elim } end
theorem
power_series.coeff_mul_X_pow
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.mem_antidiagonal", "mul_one", "mul_zero", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_X_pow_mul (p : power_series R) (n d : ℕ) : coeff R (d + n) (X ^ n * p) = coeff R d p
begin rw [coeff_mul, finset.sum_eq_single (n,d), coeff_X_pow, if_pos rfl, one_mul], { rintros ⟨i,j⟩ h1 h2, rw [coeff_X_pow, if_neg, zero_mul], rintro rfl, apply h2, rw [finset.nat.mem_antidiagonal, add_comm, add_right_cancel_iff] at h1, subst h1 }, { rw add_comm, exact λ h1, (h1 (finset.nat.mem_antidiagon...
theorem
power_series.coeff_X_pow_mul
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.mem_antidiagonal", "one_mul", "power_series", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_mul_X_pow' (p : power_series R) (n d : ℕ) : coeff R d (p * X ^ n) = ite (n ≤ d) (coeff R (d - n) p) 0
begin split_ifs, { rw [← tsub_add_cancel_of_le h, coeff_mul_X_pow, add_tsub_cancel_right] }, { refine (coeff_mul _ _ _).trans (finset.sum_eq_zero (λ x hx, _)), rw [coeff_X_pow, if_neg, mul_zero], exact ((le_of_add_le_right (finset.nat.mem_antidiagonal.mp hx).le).trans_lt $ not_le.mp h).ne } end
lemma
power_series.coeff_mul_X_pow'
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "add_tsub_cancel_right", "mul_zero", "power_series", "tsub_add_cancel_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_X_pow_mul' (p : power_series R) (n d : ℕ) : coeff R d (X ^ n * p) = ite (n ≤ d) (coeff R (d - n) p) 0
begin split_ifs, { rw [← tsub_add_cancel_of_le h, coeff_X_pow_mul], simp, }, { refine (coeff_mul _ _ _).trans (finset.sum_eq_zero (λ x hx, _)), rw [coeff_X_pow, if_neg, zero_mul], have := finset.nat.mem_antidiagonal.mp hx, rw add_comm at this, exact ((le_of_add_le_right this.le).trans_lt $ not_le....
lemma
power_series.coeff_X_pow_mul'
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series", "tsub_add_cancel_of_le", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_unit_constant_coeff (φ : power_series R) (h : is_unit φ) : is_unit (constant_coeff R φ)
mv_power_series.is_unit_constant_coeff φ h
lemma
power_series.is_unit_constant_coeff
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "is_unit", "mv_power_series.is_unit_constant_coeff", "power_series" ]
If a formal power series is invertible, then so is its constant coefficient.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_shift_mul_X_add_const (φ : power_series R) : φ = mk (λ p, coeff R (p + 1) φ) * X + C R (constant_coeff R φ)
begin ext (_ | n), { simp only [ring_hom.map_add, constant_coeff_C, constant_coeff_X, coeff_zero_eq_constant_coeff, zero_add, mul_zero, ring_hom.map_mul], }, { simp only [coeff_succ_mul_X, coeff_mk, linear_map.map_add, coeff_C, n.succ_ne_zero, sub_zero, if_false, add_zero], } end
lemma
power_series.eq_shift_mul_X_add_const
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "linear_map.map_add", "mul_zero", "power_series", "ring_hom.map_add", "ring_hom.map_mul" ]
Split off the constant coefficient.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_X_mul_shift_add_const (φ : power_series R) : φ = X * mk (λ p, coeff R (p + 1) φ) + C R (constant_coeff R φ)
begin ext (_ | n), { simp only [ring_hom.map_add, constant_coeff_C, constant_coeff_X, coeff_zero_eq_constant_coeff, zero_add, zero_mul, ring_hom.map_mul], }, { simp only [coeff_succ_X_mul, coeff_mk, linear_map.map_add, coeff_C, n.succ_ne_zero, sub_zero, if_false, add_zero], } end
lemma
power_series.eq_X_mul_shift_add_const
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "linear_map.map_add", "power_series", "ring_hom.map_add", "ring_hom.map_mul", "zero_mul" ]
Split off the constant coefficient.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map : power_series R →+* power_series S
mv_power_series.map _ f
def
power_series.map
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.map", "power_series" ]
The map between formal power series induced by a map on the coefficients.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_id : (map (ring_hom.id R) : power_series R → power_series R) = id
rfl
lemma
power_series.map_id
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "map_id", "power_series", "ring_hom.id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_comp : map (g.comp f) = (map g).comp (map f)
rfl
lemma
power_series.map_comp
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "map_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_map (n : ℕ) (φ : power_series R) : coeff S n (map f φ) = f (coeff R n φ)
rfl
lemma
power_series.coeff_map
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_C (r : R) : map f (C _ r) = C _ (f r)
by { ext, simp [coeff_C, apply_ite f] }
lemma
power_series.map_C
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "apply_ite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_X : map f X = X
by { ext, simp [coeff_X, apply_ite f] }
lemma
power_series.map_X
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "apply_ite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
X_pow_dvd_iff {n : ℕ} {φ : power_series R} : (X : power_series R)^n ∣ φ ↔ ∀ m, m < n → coeff R m φ = 0
begin convert @mv_power_series.X_pow_dvd_iff unit R _ () n φ, apply propext, classical, split; intros h m hm, { rw finsupp.unique_single m, convert h _ hm }, { apply h, simpa only [finsupp.single_eq_same] using hm } end
lemma
power_series.X_pow_dvd_iff
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finsupp.single_eq_same", "finsupp.unique_single", "mv_power_series.X_pow_dvd_iff", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
X_dvd_iff {φ : power_series R} : (X : power_series R) ∣ φ ↔ constant_coeff R φ = 0
begin rw [← pow_one (X : power_series R), X_pow_dvd_iff, ← coeff_zero_eq_constant_coeff_apply], split; intro h, { exact h 0 zero_lt_one }, { intros m hm, rwa nat.eq_zero_of_le_zero (nat.le_of_succ_le_succ hm) } end
lemma
power_series.X_dvd_iff
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "pow_one", "power_series", "zero_lt_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale (a : R) : power_series R →+* power_series R
{ to_fun := λ f, power_series.mk $ λ n, a^n * (power_series.coeff R n f), map_zero' := by { ext, simp only [linear_map.map_zero, power_series.coeff_mk, mul_zero], }, map_one' := by { ext1, simp only [mul_boole, power_series.coeff_mk, power_series.coeff_one], split_ifs, { rw [h, pow_zero], }, refl, ...
def
power_series.rescale
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.mul_sum", "linear_map.map_zero", "mul_boole", "mul_mul_mul_comm", "mul_zero", "pow_add", "pow_zero", "power_series", "power_series.coeff", "power_series.coeff_mk", "power_series.coeff_mul", "power_series.coeff_one", "power_series.mk" ]
The ring homomorphism taking a power series `f(X)` to `f(aX)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_rescale (f : power_series R) (a : R) (n : ℕ) : coeff R n (rescale a f) = a^n * coeff R n f
coeff_mk n _
lemma
power_series.coeff_rescale
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_zero : rescale 0 = (C R).comp (constant_coeff R)
begin ext, simp only [function.comp_app, ring_hom.coe_comp, rescale, ring_hom.coe_mk, power_series.coeff_mk _ _, coeff_C], split_ifs, { simp only [h, one_mul, coeff_zero_eq_constant_coeff, pow_zero], }, { rw [zero_pow' n h, zero_mul], }, end
lemma
power_series.rescale_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "one_mul", "pow_zero", "power_series.coeff_mk", "ring_hom.coe_comp", "ring_hom.coe_mk", "zero_mul", "zero_pow'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_zero_apply : rescale 0 X = C R (constant_coeff R X)
by simp
lemma
power_series.rescale_zero_apply
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_one : rescale 1 = ring_hom.id (power_series R)
by { ext, simp only [ring_hom.id_apply, rescale, one_pow, coeff_mk, one_mul, ring_hom.coe_mk], }
lemma
power_series.rescale_one
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "one_mul", "one_pow", "power_series", "ring_hom.coe_mk", "ring_hom.id", "ring_hom.id_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_mk (f : ℕ → R) (a : R) : rescale a (mk f) = mk (λ n : ℕ, a^n * (f n))
by { ext, rw [coeff_rescale, coeff_mk, coeff_mk], }
lemma
power_series.rescale_mk
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_rescale (f : power_series R) (a b : R) : rescale b (rescale a f) = rescale (a * b) f
begin ext, repeat { rw coeff_rescale, }, rw [mul_pow, mul_comm _ (b^n), mul_assoc], end
lemma
power_series.rescale_rescale
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mul_assoc", "mul_comm", "mul_pow", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_mul (a b : R) : rescale (a * b) = (rescale b).comp (rescale a)
by { ext, simp [← rescale_rescale], }
lemma
power_series.rescale_mul
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trunc (n : ℕ) (φ : power_series R) : R[X]
∑ m in Ico 0 n, polynomial.monomial m (coeff R m φ)
def
power_series.trunc
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "polynomial.monomial", "power_series", "trunc" ]
The `n`th truncation of a formal power series to a polynomial
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_trunc (m) (n) (φ : power_series R) : (trunc n φ).coeff m = if m < n then coeff R m φ else 0
by simp [trunc, polynomial.coeff_sum, polynomial.coeff_monomial, nat.lt_succ_iff]
lemma
power_series.coeff_trunc
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "nat.lt_succ_iff", "polynomial.coeff_monomial", "polynomial.coeff_sum", "power_series", "trunc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trunc_zero (n) : trunc n (0 : power_series R) = 0
polynomial.ext $ λ m, begin rw [coeff_trunc, linear_map.map_zero, polynomial.coeff_zero], split_ifs; refl end
lemma
power_series.trunc_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "linear_map.map_zero", "polynomial.coeff_zero", "polynomial.ext", "power_series", "trunc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trunc_one (n) : trunc (n + 1) (1 : power_series R) = 1
polynomial.ext $ λ m, begin rw [coeff_trunc, coeff_one], split_ifs with H H' H'; rw [polynomial.coeff_one], { subst m, rw [if_pos rfl] }, { symmetry, exact if_neg (ne.elim (ne.symm H')) }, { symmetry, refine if_neg _, rintro rfl, apply H, exact nat.zero_lt_succ _ } end
lemma
power_series.trunc_one
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "polynomial.coeff_one", "polynomial.ext", "power_series", "trunc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trunc_C (n) (a : R) : trunc (n + 1) (C R a) = polynomial.C a
polynomial.ext $ λ m, begin rw [coeff_trunc, coeff_C, polynomial.coeff_C], split_ifs with H; refl <|> try {simp * at *} end
lemma
power_series.trunc_C
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "polynomial.C", "polynomial.coeff_C", "polynomial.ext", "trunc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trunc_add (n) (φ ψ : power_series R) : trunc n (φ + ψ) = trunc n φ + trunc n ψ
polynomial.ext $ λ m, begin simp only [coeff_trunc, add_monoid_hom.map_add, polynomial.coeff_add], split_ifs with H, {refl}, {rw [zero_add]} end
lemma
power_series.trunc_add
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "polynomial.coeff_add", "polynomial.ext", "power_series", "trunc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv.aux : R → power_series R → power_series R
mv_power_series.inv.aux
def
power_series.inv.aux
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.inv.aux", "power_series" ]
Auxiliary function used for computing inverse of a power series
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_inv_aux (n : ℕ) (a : R) (φ : power_series R) : coeff R n (inv.aux a φ) = if n = 0 then a else - a * ∑ x in finset.nat.antidiagonal n, if x.2 < n then coeff R x.1 φ * coeff R x.2 (inv.aux a φ) else 0
begin rw [coeff, inv.aux, mv_power_series.coeff_inv_aux], simp only [finsupp.single_eq_zero], split_ifs, {refl}, congr' 1, symmetry, apply finset.sum_bij (λ (p : ℕ × ℕ) h, (single () p.1, single () p.2)), { rintros ⟨i,j⟩ hij, rw finset.nat.mem_antidiagonal at hij, rw [finsupp.mem_antidiagonal, ← finsu...
lemma
power_series.coeff_inv_aux
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.antidiagonal", "finset.nat.mem_antidiagonal", "finsupp.add_apply", "finsupp.mem_antidiagonal", "finsupp.single_add", "finsupp.single_eq_same", "finsupp.single_eq_zero", "finsupp.unique_single", "finsupp.unique_single_eq_iff", "mv_power_series.coeff_inv_aux", "power_series", "prod.m...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_of_unit (φ : power_series R) (u : Rˣ) : power_series R
mv_power_series.inv_of_unit φ u
def
power_series.inv_of_unit
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.inv_of_unit", "power_series" ]
A formal power series is invertible if the constant coefficient is invertible.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_inv_of_unit (n : ℕ) (φ : power_series R) (u : Rˣ) : coeff R n (inv_of_unit φ u) = if n = 0 then ↑u⁻¹ else - ↑u⁻¹ * ∑ x in finset.nat.antidiagonal n, if x.2 < n then coeff R x.1 φ * coeff R x.2 (inv_of_unit φ u) else 0
coeff_inv_aux n ↑u⁻¹ φ
lemma
power_series.coeff_inv_of_unit
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.antidiagonal", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
constant_coeff_inv_of_unit (φ : power_series R) (u : Rˣ) : constant_coeff R (inv_of_unit φ u) = ↑u⁻¹
by rw [← coeff_zero_eq_constant_coeff_apply, coeff_inv_of_unit, if_pos rfl]
lemma
power_series.constant_coeff_inv_of_unit
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_of_unit (φ : power_series R) (u : Rˣ) (h : constant_coeff R φ = u) : φ * inv_of_unit φ u = 1
mv_power_series.mul_inv_of_unit φ u $ h
lemma
power_series.mul_inv_of_unit
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.mul_inv_of_unit", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_const_eq_shift_mul_X (φ : power_series R) : φ - C R (constant_coeff R φ) = power_series.mk (λ p, coeff R (p + 1) φ) * X
sub_eq_iff_eq_add.mpr (eq_shift_mul_X_add_const φ)
lemma
power_series.sub_const_eq_shift_mul_X
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series", "power_series.mk" ]
Two ways of removing the constant coefficient of a power series are the same.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_const_eq_X_mul_shift (φ : power_series R) : φ - C R (constant_coeff R φ) = X * power_series.mk (λ p, coeff R (p + 1) φ)
sub_eq_iff_eq_add.mpr (eq_X_mul_shift_add_const φ)
lemma
power_series.sub_const_eq_X_mul_shift
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series", "power_series.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_X (a : A) : rescale a X = C A a * X
begin ext, simp only [coeff_rescale, coeff_C_mul, coeff_X], split_ifs with h; simp [h], end
lemma
power_series.rescale_X
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_neg_one_X : rescale (-1 : A) X = -X
by rw [rescale_X, map_neg, map_one, neg_one_mul]
lemma
power_series.rescale_neg_one_X
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "map_one", "neg_one_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval_neg_hom : power_series A →+* power_series A
rescale (-1 : A)
def
power_series.eval_neg_hom
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
The ring homomorphism taking a power series `f(X)` to `f(-X)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eval_neg_hom_X : eval_neg_hom (X : power_series A) = -X
rescale_neg_one_X
lemma
power_series.eval_neg_hom_X
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_zero_or_eq_zero_of_mul_eq_zero [no_zero_divisors R] (φ ψ : power_series R) (h : φ * ψ = 0) : φ = 0 ∨ ψ = 0
begin rw or_iff_not_imp_left, intro H, have ex : ∃ m, coeff R m φ ≠ 0, { contrapose! H, exact ext H }, let m := nat.find ex, have hm₁ : coeff R m φ ≠ 0 := nat.find_spec ex, have hm₂ : ∀ k < m, ¬coeff R k φ ≠ 0 := λ k, nat.find_min ex, ext n, rw (coeff R n).map_zero, apply nat.strong_induction_on n, clear ...
lemma
power_series.eq_zero_or_eq_zero_of_mul_eq_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.mem_antidiagonal", "ih", "linear_map.map_zero", "mul_zero", "no_zero_divisors", "or_iff_not_imp_left", "power_series", "prod.mk.inj_iff", "zero_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
span_X_is_prime : (ideal.span ({X} : set (power_series R))).is_prime
begin suffices : ideal.span ({X} : set (power_series R)) = (constant_coeff R).ker, { rw this, exact ring_hom.ker_is_prime _ }, apply ideal.ext, intro φ, rw [ring_hom.mem_ker, ideal.mem_span_singleton, X_dvd_iff] end
lemma
power_series.span_X_is_prime
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "ideal.ext", "ideal.mem_span_singleton", "ideal.span", "power_series", "ring_hom.ker_is_prime", "ring_hom.mem_ker" ]
The ideal spanned by the variable in the power series ring over an integral domain is a prime ideal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
X_prime : prime (X : power_series R)
begin rw ← ideal.span_singleton_prime, { exact span_X_is_prime }, { intro h, simpa using congr_arg (coeff R 1) h } end
lemma
power_series.X_prime
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "ideal.span_singleton_prime", "power_series", "prime" ]
The variable of the power series ring over an integral domain is prime.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
rescale_injective {a : R} (ha : a ≠ 0) : function.injective (rescale a)
begin intros p q h, rw power_series.ext_iff at *, intros n, specialize h n, rw [coeff_rescale, coeff_rescale, mul_eq_mul_left_iff] at h, apply h.resolve_right, intro h', exact ha (pow_eq_zero h'), end
lemma
power_series.rescale_injective
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mul_eq_mul_left_iff", "pow_eq_zero", "power_series.ext_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map.is_local_ring_hom : is_local_ring_hom (map f)
mv_power_series.map.is_local_ring_hom f
instance
power_series.map.is_local_ring_hom
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "is_local_ring_hom", "mv_power_series.map.is_local_ring_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
C_eq_algebra_map {r : R} : C R r = (algebra_map R (power_series R)) r
rfl
theorem
power_series.C_eq_algebra_map
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "algebra_map", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
algebra_map_apply {r : R} : algebra_map R (power_series A) r = C A (algebra_map R A r)
mv_power_series.algebra_map_apply
theorem
power_series.algebra_map_apply
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "algebra_map", "algebra_map_apply", "mv_power_series.algebra_map_apply", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv : power_series k → power_series k
mv_power_series.inv
def
power_series.inv
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.inv", "power_series" ]
The inverse 1/f of a power series f defined over a field
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_eq_inv_aux (φ : power_series k) : φ⁻¹ = inv.aux (constant_coeff k φ)⁻¹ φ
rfl
lemma
power_series.inv_eq_inv_aux
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_inv (n) (φ : power_series k) : coeff k n (φ⁻¹) = if n = 0 then (constant_coeff k φ)⁻¹ else - (constant_coeff k φ)⁻¹ * ∑ x in finset.nat.antidiagonal n, if x.2 < n then coeff k x.1 φ * coeff k x.2 (φ⁻¹) else 0
by rw [inv_eq_inv_aux, coeff_inv_aux n (constant_coeff k φ)⁻¹ φ]
lemma
power_series.coeff_inv
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.antidiagonal", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
constant_coeff_inv (φ : power_series k) : constant_coeff k (φ⁻¹) = (constant_coeff k φ)⁻¹
mv_power_series.constant_coeff_inv φ
lemma
power_series.constant_coeff_inv
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.constant_coeff_inv", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_eq_zero {φ : power_series k} : φ⁻¹ = 0 ↔ constant_coeff k φ = 0
mv_power_series.inv_eq_zero
lemma
power_series.inv_eq_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "inv_eq_zero", "mv_power_series.inv_eq_zero", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_inv : (0 : power_series k)⁻¹ = 0
mv_power_series.zero_inv
lemma
power_series.zero_inv
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.zero_inv", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_of_unit_eq (φ : power_series k) (h : constant_coeff k φ ≠ 0) : inv_of_unit φ (units.mk0 _ h) = φ⁻¹
mv_power_series.inv_of_unit_eq _ _
lemma
power_series.inv_of_unit_eq
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.inv_of_unit_eq", "power_series", "units.mk0" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_of_unit_eq' (φ : power_series k) (u : units k) (h : constant_coeff k φ = u) : inv_of_unit φ u = φ⁻¹
mv_power_series.inv_of_unit_eq' φ _ h
lemma
power_series.inv_of_unit_eq'
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.inv_of_unit_eq'", "power_series", "units" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_cancel (φ : power_series k) (h : constant_coeff k φ ≠ 0) : φ * φ⁻¹ = 1
mv_power_series.mul_inv_cancel φ h
lemma
power_series.mul_inv_cancel
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mul_inv_cancel", "mv_power_series.mul_inv_cancel", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_mul_cancel (φ : power_series k) (h : constant_coeff k φ ≠ 0) : φ⁻¹ * φ = 1
mv_power_series.inv_mul_cancel φ h
lemma
power_series.inv_mul_cancel
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "inv_mul_cancel", "mv_power_series.inv_mul_cancel", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_mul_inv_iff_mul_eq {φ₁ φ₂ φ₃ : power_series k} (h : constant_coeff k φ₃ ≠ 0) : φ₁ = φ₂ * φ₃⁻¹ ↔ φ₁ * φ₃ = φ₂
mv_power_series.eq_mul_inv_iff_mul_eq h
lemma
power_series.eq_mul_inv_iff_mul_eq
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "eq_mul_inv_iff_mul_eq", "mv_power_series.eq_mul_inv_iff_mul_eq", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_inv_iff_mul_eq_one {φ ψ : power_series k} (h : constant_coeff k ψ ≠ 0) : φ = ψ⁻¹ ↔ φ * ψ = 1
mv_power_series.eq_inv_iff_mul_eq_one h
lemma
power_series.eq_inv_iff_mul_eq_one
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "eq_inv_iff_mul_eq_one", "mv_power_series.eq_inv_iff_mul_eq_one", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_eq_iff_mul_eq_one {φ ψ : power_series k} (h : constant_coeff k ψ ≠ 0) : ψ⁻¹ = φ ↔ φ * ψ = 1
mv_power_series.inv_eq_iff_mul_eq_one h
lemma
power_series.inv_eq_iff_mul_eq_one
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "inv_eq_iff_mul_eq_one", "mv_power_series.inv_eq_iff_mul_eq_one", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_inv_rev (φ ψ : power_series k) : (φ * ψ)⁻¹ = ψ⁻¹ * φ⁻¹
mv_power_series.mul_inv_rev _ _
lemma
power_series.mul_inv_rev
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mul_inv_rev", "mv_power_series.mul_inv_rev", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
C_inv (r : k) : (C k r)⁻¹ = C k r⁻¹
mv_power_series.C_inv _
lemma
power_series.C_inv
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.C_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
X_inv : (X : power_series k)⁻¹ = 0
mv_power_series.X_inv _
lemma
power_series.X_inv
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.X_inv", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
smul_inv (r : k) (φ : power_series k) : (r • φ)⁻¹ = r⁻¹ • φ⁻¹
mv_power_series.smul_inv _ _
lemma
power_series.smul_inv
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "mv_power_series.smul_inv", "power_series", "smul_inv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_coeff_ne_zero_iff_ne_zero : (∃ (n : ℕ), coeff R n φ ≠ 0) ↔ φ ≠ 0
begin refine not_iff_not.mp _, push_neg, simp [power_series.ext_iff] end
lemma
power_series.exists_coeff_ne_zero_iff_ne_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series.ext_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order (φ : power_series R) : part_enat
if h : φ = 0 then ⊤ else nat.find (exists_coeff_ne_zero_iff_ne_zero.mpr h)
def
power_series.order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "part_enat", "power_series" ]
The order of a formal power series `φ` is the greatest `n : part_enat` such that `X^n` divides `φ`. The order is `⊤` if and only if `φ = 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_zero : order (0 : power_series R) = ⊤
dif_pos rfl
lemma
power_series.order_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
The order of the `0` power series is infinite.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_finite_iff_ne_zero : (order φ).dom ↔ φ ≠ 0
begin simp only [order], split, { split_ifs with h h; intro H, { contrapose! H, simpa [←part.eq_none_iff'] }, { exact h } }, { intro h, simp [h] } end
lemma
power_series.order_finite_iff_ne_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_order (h : (order φ).dom) : coeff R (φ.order.get h) φ ≠ 0
begin simp only [order, order_finite_iff_ne_zero.mp h, not_false_iff, dif_neg, part_enat.get_coe'], generalize_proofs h, exact nat.find_spec h end
lemma
power_series.coeff_order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "part_enat.get_coe'" ]
If the order of a formal power series is finite, then the coefficient indexed by the order is nonzero.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_le (n : ℕ) (h : coeff R n φ ≠ 0) : order φ ≤ n
begin have := exists.intro n h, rw [order, dif_neg], { simp only [part_enat.coe_le_coe, nat.find_le_iff], exact ⟨n, le_rfl, h⟩ }, { exact exists_coeff_ne_zero_iff_ne_zero.mp ⟨n, h⟩ } end
lemma
power_series.order_le
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "le_rfl", "nat.find_le_iff", "part_enat.coe_le_coe" ]
If the `n`th coefficient of a formal power series is nonzero, then the order of the power series is less than or equal to `n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_of_lt_order (n : ℕ) (h: ↑n < order φ) : coeff R n φ = 0
by { contrapose! h, exact order_le _ h }
lemma
power_series.coeff_of_lt_order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[]
The `n`th coefficient of a formal power series is `0` if `n` is strictly smaller than the order of the power series.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_eq_top {φ : power_series R} : φ.order = ⊤ ↔ φ = 0
begin split, { intro h, ext n, rw [(coeff R n).map_zero, coeff_of_lt_order], simp [h] }, { rintros rfl, exact order_zero } end
lemma
power_series.order_eq_top
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
The `0` power series is the unique power series with infinite order.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_le_order (φ : power_series R) (n : ℕ) (h : ∀ i < n, coeff R i φ = 0) : ↑n ≤ order φ
begin by_contra H, rw not_le at H, have : (order φ).dom := part_enat.dom_of_le_coe H.le, rw [← part_enat.coe_get this, part_enat.coe_lt_coe] at H, exact coeff_order this (h _ H) end
lemma
power_series.nat_le_order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "by_contra", "part_enat.coe_get", "part_enat.coe_lt_coe", "part_enat.dom_of_le_coe", "power_series" ]
The order of a formal power series is at least `n` if the `i`th coefficient is `0` for all `i < n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_order (φ : power_series R) (n : part_enat) (h : ∀ i : ℕ, ↑i < n → coeff R i φ = 0) : n ≤ order φ
begin induction n using part_enat.cases_on, { show _ ≤ _, rw [top_le_iff, order_eq_top], ext i, exact h _ (part_enat.coe_lt_top i) }, { apply nat_le_order, simpa only [part_enat.coe_lt_coe] using h } end
lemma
power_series.le_order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "part_enat", "part_enat.cases_on", "part_enat.coe_lt_coe", "part_enat.coe_lt_top", "power_series", "top_le_iff" ]
The order of a formal power series is at least `n` if the `i`th coefficient is `0` for all `i < n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_eq_nat {φ : power_series R} {n : ℕ} : order φ = n ↔ (coeff R n φ ≠ 0) ∧ (∀ i, i < n → coeff R i φ = 0)
begin rcases eq_or_ne φ 0 with rfl|hφ, { simpa using (part_enat.coe_ne_top _).symm }, simp [order, dif_neg hφ, nat.find_eq_iff] end
lemma
power_series.order_eq_nat
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "eq_or_ne", "nat.find_eq_iff", "part_enat.coe_ne_top", "power_series" ]
The order of a formal power series is exactly `n` if the `n`th coefficient is nonzero, and the `i`th coefficient is `0` for all `i < n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_eq {φ : power_series R} {n : part_enat} : order φ = n ↔ (∀ i:ℕ, ↑i = n → coeff R i φ ≠ 0) ∧ (∀ i:ℕ, ↑i < n → coeff R i φ = 0)
begin induction n using part_enat.cases_on, { rw order_eq_top, split, { rintro rfl, split; intros, { exfalso, exact part_enat.coe_ne_top ‹_› ‹_› }, { exact (coeff _ _).map_zero } }, { rintro ⟨h₁, h₂⟩, ext i, exact h₂ i (part_enat.coe_lt_top i) } }, { simpa [part_enat.coe_inj] using order_eq_na...
lemma
power_series.order_eq
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "part_enat", "part_enat.cases_on", "part_enat.coe_inj", "part_enat.coe_lt_top", "part_enat.coe_ne_top", "power_series" ]
The order of a formal power series is exactly `n` if the `n`th coefficient is nonzero, and the `i`th coefficient is `0` for all `i < n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_order_add (φ ψ : power_series R) : min (order φ) (order ψ) ≤ order (φ + ψ)
begin refine le_order _ _ _, simp [coeff_of_lt_order] {contextual := tt} end
lemma
power_series.le_order_add
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
The order of the sum of two formal power series is at least the minimum of their orders.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_add_of_order_eq.aux (φ ψ : power_series R) (h : order φ ≠ order ψ) (H : order φ < order ψ) : order (φ + ψ) ≤ order φ ⊓ order ψ
begin suffices : order (φ + ψ) = order φ, { rw [le_inf_iff, this], exact ⟨le_rfl, le_of_lt H⟩ }, { rw order_eq, split, { intros i hi, rw ←hi at H, rw [(coeff _ _).map_add, coeff_of_lt_order i H, add_zero], exact (order_eq_nat.1 hi.symm).1 }, { intros i hi, rw [(coeff _ _).map_add, coeff_of_lt_...
lemma
power_series.order_add_of_order_eq.aux
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "le_inf_iff", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_add_of_order_eq (φ ψ : power_series R) (h : order φ ≠ order ψ) : order (φ + ψ) = order φ ⊓ order ψ
begin refine le_antisymm _ (le_order_add _ _), by_cases H₁ : order φ < order ψ, { apply order_add_of_order_eq.aux _ _ h H₁ }, by_cases H₂ : order ψ < order φ, { simpa only [add_comm, inf_comm] using order_add_of_order_eq.aux _ _ h.symm H₂ }, exfalso, exact h (le_antisymm (not_lt.1 H₂) (not_lt.1 H₁)) end
lemma
power_series.order_add_of_order_eq
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "inf_comm", "power_series" ]
The order of the sum of two formal power series is the minimum of their orders if their orders differ.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_mul_ge (φ ψ : power_series R) : order φ + order ψ ≤ order (φ * ψ)
begin apply le_order, intros n hn, rw [coeff_mul, finset.sum_eq_zero], rintros ⟨i,j⟩ hij, by_cases hi : ↑i < order φ, { rw [coeff_of_lt_order i hi, zero_mul] }, by_cases hj : ↑j < order ψ, { rw [coeff_of_lt_order j hj, mul_zero] }, rw not_lt at hi hj, rw finset.nat.mem_antidiagonal at hij, exfalso, ...
lemma
power_series.order_mul_ge
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.mem_antidiagonal", "mul_zero", "nat.cast_add", "power_series", "zero_mul" ]
The order of the product of two formal power series is at least the sum of their orders.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_monomial (n : ℕ) (a : R) [decidable (a = 0)] : order (monomial R n a) = if a = 0 then ⊤ else n
begin split_ifs with h, { rw [h, order_eq_top, linear_map.map_zero] }, { rw [order_eq], split; intros i hi, { rw [part_enat.coe_inj] at hi, rwa [hi, coeff_monomial_same] }, { rw [part_enat.coe_lt_coe] at hi, rw [coeff_monomial, if_neg], exact ne_of_lt hi } } end
lemma
power_series.order_monomial
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "linear_map.map_zero", "part_enat.coe_inj", "part_enat.coe_lt_coe" ]
The order of the monomial `a*X^n` is infinite if `a = 0` and `n` otherwise.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_monomial_of_ne_zero (n : ℕ) (a : R) (h : a ≠ 0) : order (monomial R n a) = n
by rw [order_monomial, if_neg h]
lemma
power_series.order_monomial_of_ne_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[]
The order of the monomial `a*X^n` is `n` if `a ≠ 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_mul_of_lt_order {φ ψ : power_series R} {n : ℕ} (h : ↑n < ψ.order) : coeff R n (φ * ψ) = 0
begin suffices : coeff R n (φ * ψ) = ∑ p in finset.nat.antidiagonal n, 0, rw [this, finset.sum_const_zero], rw [coeff_mul], apply finset.sum_congr rfl (λ x hx, _), refine mul_eq_zero_of_right (coeff R x.fst φ) (coeff_of_lt_order x.snd (lt_of_le_of_lt _ h)), rw finset.nat.mem_antidiagonal at hx, norm_cas...
lemma
power_series.coeff_mul_of_lt_order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finset.nat.antidiagonal", "finset.nat.mem_antidiagonal", "mul_eq_zero_of_right", "power_series" ]
If `n` is strictly smaller than the order of `ψ`, then the `n`th coefficient of its product with any other power series is `0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_mul_one_sub_of_lt_order {R : Type*} [comm_ring R] {φ ψ : power_series R} (n : ℕ) (h : ↑n < ψ.order) : coeff R n (φ * (1 - ψ)) = coeff R n φ
by simp [coeff_mul_of_lt_order h, mul_sub]
lemma
power_series.coeff_mul_one_sub_of_lt_order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "comm_ring", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_mul_prod_one_sub_of_lt_order {R ι : Type*} [comm_ring R] (k : ℕ) (s : finset ι) (φ : power_series R) (f : ι → power_series R) : (∀ i ∈ s, ↑k < (f i).order) → coeff R k (φ * ∏ i in s, (1 - f i)) = coeff R k φ
begin apply finset.induction_on s, { simp }, { intros a s ha ih t, simp only [finset.mem_insert, forall_eq_or_imp] at t, rw [finset.prod_insert ha, ← mul_assoc, mul_right_comm, coeff_mul_one_sub_of_lt_order _ t.1], exact ih t.2 }, end
lemma
power_series.coeff_mul_prod_one_sub_of_lt_order
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "comm_ring", "finset", "finset.induction_on", "finset.mem_insert", "finset.prod_insert", "forall_eq_or_imp", "ih", "mul_assoc", "mul_right_comm", "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
X_pow_order_dvd (h : (order φ).dom) : X ^ ((order φ).get h) ∣ φ
begin refine ⟨power_series.mk (λ n, coeff R (n + (order φ).get h) φ), _⟩, ext n, simp only [coeff_mul, coeff_X_pow, coeff_mk, boole_mul, finset.sum_ite, finset.nat.filter_fst_eq_antidiagonal, finset.sum_const_zero, add_zero], split_ifs with hn hn, { simp [tsub_add_cancel_of_le hn] }, { simp onl...
lemma
power_series.X_pow_order_dvd
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "boole_mul", "finset.nat.filter_fst_eq_antidiagonal", "part_enat.coe_lt_iff", "tsub_add_cancel_of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_eq_multiplicity_X {R : Type*} [semiring R] (φ : power_series R) : order φ = multiplicity X φ
begin rcases eq_or_ne φ 0 with rfl|hφ, { simp }, induction ho : order φ using part_enat.cases_on with n, { simpa [hφ] using ho }, have hn : φ.order.get (order_finite_iff_ne_zero.mpr hφ) = n, { simp [ho] }, rw ←hn, refine le_antisymm (le_multiplicity_of_pow_dvd $ X_pow_order_dvd (order_finite_iff_ne_...
lemma
power_series.order_eq_multiplicity_X
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "eq_or_ne", "multiplicity", "part_enat.cases_on", "part_enat.coe_lt_coe", "part_enat.coe_lt_top", "part_enat.find_le", "power_series", "semiring" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_one : order (1 : power_series R) = 0
by simpa using order_monomial_of_ne_zero 0 (1:R) one_ne_zero
lemma
power_series.order_one
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "one_ne_zero", "power_series" ]
The order of the formal power series `1` is `0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_X : order (X : power_series R) = 1
by simpa only [nat.cast_one] using order_monomial_of_ne_zero 1 (1:R) one_ne_zero
lemma
power_series.order_X
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "nat.cast_one", "one_ne_zero", "power_series" ]
The order of the formal power series `X` is `1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_X_pow (n : ℕ) : order ((X : power_series R)^n) = n
by { rw [X_pow_eq, order_monomial_of_ne_zero], exact one_ne_zero }
lemma
power_series.order_X_pow
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "one_ne_zero", "power_series" ]
The order of the formal power series `X^n` is `n`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
order_mul (φ ψ : power_series R) : order (φ * ψ) = order φ + order ψ
begin simp_rw [order_eq_multiplicity_X], exact multiplicity.mul X_prime end
lemma
power_series.order_mul
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "multiplicity.mul", "power_series" ]
The order of the product of two formal power series over an integral domain is the sum of their orders.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_to_power_series : has_coe R[X] (power_series R)
⟨λ φ, power_series.mk $ λ n, coeff φ n⟩
instance
polynomial.coe_to_power_series
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series", "power_series.mk" ]
The natural inclusion from polynomials into formal power series.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_def : (φ : power_series R) = power_series.mk (coeff φ)
rfl
lemma
polynomial.coe_def
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series", "power_series.mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coeff_coe (n) : power_series.coeff R n φ = coeff φ n
congr_arg (coeff φ) (finsupp.single_eq_same)
lemma
polynomial.coeff_coe
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "finsupp.single_eq_same", "power_series.coeff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_monomial (n : ℕ) (a : R) : (monomial n a : power_series R) = power_series.monomial R n a
by { ext, simp [coeff_coe, power_series.coeff_monomial, polynomial.coeff_monomial, eq_comm] }
lemma
polynomial.coe_monomial
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "polynomial.coeff_monomial", "power_series", "power_series.coeff_monomial", "power_series.monomial" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_zero : ((0 : R[X]) : power_series R) = 0
rfl
lemma
polynomial.coe_zero
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_one : ((1 : R[X]) : power_series R) = 1
begin have := coe_monomial 0 (1:R), rwa power_series.monomial_zero_eq_C_apply at this, end
lemma
polynomial.coe_one
ring_theory.power_series
src/ring_theory/power_series/basic.lean
[ "data.finsupp.interval", "data.mv_polynomial.basic", "data.polynomial.algebra_map", "data.polynomial.coeff", "linear_algebra.std_basis", "ring_theory.ideal.local_ring", "ring_theory.multiplicity", "tactic.linarith" ]
[ "power_series", "power_series.monomial_zero_eq_C_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83