mathlib-initiative/mathlib-tactics huggingface dataset:
Module: Mathlib.RingTheory.HahnSeries.Binomial

Goal state before:
pp: case inr.right.refine_1
Γ : Type u_1
R : Type u_2
A : Type u_3
inst✝⁶ : LinearOrder Γ
inst✝⁵ : AddCommMonoid Γ
inst✝⁴ : IsOrderedCancelAddMonoid Γ
inst✝³ : CommRing R
inst✝² : BinomialRing R
inst✝¹ : CommRing A
inst✝ : Algebra R A
x : A⟦Γ⟧
hx : 0 < (x - 1).orderTop
r : R
h✝ : Nontrivial A
this : ((binomialFamily x r) 0).coeff 0 = 1
⊢ ∀ (b : ℕ), ∀ g' ∈ ((binomialFamily x r) b).support, 0 ≤ g'

Tactic:
intro b g' hg'
        exact binomialFamily_mem_support hx r b hg'

Goal state after:
Module: Mathlib.RingTheory.Ideal.HasGoingUp

Goal state before:
pp: R : Type u_1
S : Type u_2
inst✝⁴ : CommRing R
inst✝³ : CommRing S
inst✝² : Algebra R S
inst✝¹ : Algebra.HasGoingUp R S
l : RelSeries {(a, b) | a < b}
q : PrimeSpectrum R
P : Ideal S
inst✝ : P.IsPrime
Q : Ideal S
hQ : Q.IsPrime
L : LTSeries (PrimeSpectrum S)
lt : q < l.head
ih :
  ∀ (P : Ideal S) [inst : P.IsPrime] [lo : P.LiesOver l.head.asIdeal],
    ∃ L,
      L.length = l.length ∧
        RelSeries.head L = { asIdeal := P, isPrime := ⋯ } ∧
          List.map (PrimeSpectrum.comap (algebraMap R S)) (RelSeries.toList L) = l.toList
lo : P.LiesOver q.asIdeal
PQlt : P < Q
Qlo : Q.LiesOver l.head.asIdeal
len : L.length = l.length
head : RelSeries.head L = { asIdeal := Q, isPrime := ⋯ }
spec : List.map (PrimeSpectrum.comap (algebraMap R S)) (RelSeries.toList L) = l.toList
⊢ { asIdeal := P, isPrime := ⋯ } < { asIdeal := Q, isPrime := ⋯ }

Tactic:
exact PQlt

Goal state after:
Module: Mathlib.RingTheory.Ideal.IsAugmentation

Goal state before:
pp: R : Type u_1
inst✝² : CommSemiring R
A : Type u_2
inst✝¹ : CommSemiring A
inst✝ : Algebra R A
S : Subalgebra R A
I : Ideal A
⊢ IsAugmentation (↥S) I ↔ IsCompl (toSubmodule S) (Submodule.restrictScalars R I)

Tactic:
simp [Ideal.IsAugmentation, ← Submodule.isCompl_restrictScalars_iff R]

Goal state after:
Module: Mathlib.RingTheory.Henselian

Goal state before:
pp: case refine_1
R : Type u_1
inst✝¹ : CommRing R
I : Ideal R
inst✝ : IsAdicComplete I R
f : R[X]
x✝ : f.Monic
a₀ : R
h₁ : Polynomial.eval a₀ f ∈ I
h₂ : IsUnit ((Ideal.Quotient.mk I) (Polynomial.eval a₀ (derivative f)))
f' : R[X] := derivative f
c : ℕ → R := fun n ↦ Nat.recOn n a₀ fun x b ↦ b - Polynomial.eval b f * (Polynomial.eval b f')⁻¹ʳ
hc : ∀ (n : ℕ), c (n + 1) = c n - Polynomial.eval (c n) f * (Polynomial.eval (c n) f')⁻¹ʳ
hc_mod : ∀ (n : ℕ), c n ≡ a₀ [SMOD I]
hf'c : ∀ (n : ℕ), IsUnit (Polynomial.eval (c n) f')
hfcI : ∀ (n : ℕ), Polynomial.eval (c n) f ∈ I ^ (n + 1)
aux : ∀ (m n : ℕ), m ≤ n → c m ≡ c n [SMOD I ^ m • ⊤]
a : R
n : ℕ
ha : c n ≡ a [SMOD I ^ n]
⊢ Polynomial.eval (c n) f ≡ 0 [SMOD I ^ n]

Tactic:
rw [SModEq.zero]

Goal state after:
case refine_1
R : Type u_1
inst✝¹ : CommRing R
I : Ideal R
inst✝ : IsAdicComplete I R
f : R[X]
x✝ : f.Monic
a₀ : R
h₁ : Polynomial.eval a₀ f ∈ I
h₂ : IsUnit ((Ideal.Quotient.mk I) (Polynomial.eval a₀ (derivative f)))
f' : R[X] := derivative f
c : ℕ → R := fun n ↦ Nat.recOn n a₀ fun x b ↦ b - Polynomial.eval b f * (Polynomial.eval b f')⁻¹ʳ
hc : ∀ (n : ℕ), c (n + 1) = c n - Polynomial.eval (c n) f * (Polynomial.eval (c n) f')⁻¹ʳ
hc_mod : ∀ (n : ℕ), c n ≡ a₀ [SMOD I]
hf'c : ∀ (n : ℕ), IsUnit (Polynomial.eval (c n) f')
hfcI : ∀ (n : ℕ), Polynomial.eval (c n) f ∈ I ^ (n + 1)
aux : ∀ (m n : ℕ), m ≤ n → c m ≡ c n [SMOD I ^ m • ⊤]
a : R
n : ℕ
ha : c n ≡ a [SMOD I ^ n]
⊢ Polynomial.eval (c n) f ∈ I ^ n
Module: Mathlib.RingTheory.Ideal.MonicSpan

Goal state before:
pp: R : Type u_1
inst✝ : CommRing R
p : Ideal R[X]
ism : (comap C p).IsMaximal
ne : p ≠ Ideal.map C (comap C p)
q : Ideal R := comap C p
this✝ : Field (R ⧸ q) := Quotient.field q
ne' : Ideal.map (mapRingHom (Ideal.Quotient.mk q)) p ≠ ⊥
y : (R ⧸ q)[X]
mony : y.Monic
hy : Ideal.map (mapRingHom (Ideal.Quotient.mk q)) p = span {y}
this : y ∈ lifts (Ideal.Quotient.mk q)
f : R[X]
hf : map (Ideal.Quotient.mk q) f = y
deg : f.natDegree = y.natDegree
monf : f.Monic
⊢ p = comap (mapRingHom (Ideal.Quotient.mk q)) (span (⇑(mapRingHom (Ideal.Quotient.mk q)) '' {f}))

Tactic:
coe_mapRingHom,

Goal state after:
R : Type u_1
inst✝ : CommRing R
p : Ideal R[X]
ism : (comap C p).IsMaximal
ne : p ≠ Ideal.map C (comap C p)
q : Ideal R := comap C p
this✝ : Field (R ⧸ q) := Quotient.field q
ne' : Ideal.map (mapRingHom (Ideal.Quotient.mk q)) p ≠ ⊥
y : (R ⧸ q)[X]
mony : y.Monic
hy : Ideal.map (mapRingHom (Ideal.Quotient.mk q)) p = span {y}
this : y ∈ lifts (Ideal.Quotient.mk q)
f : R[X]
hf : map (Ideal.Quotient.mk q) f = y
deg : f.natDegree = y.natDegree
monf : f.Monic
⊢ p = comap (mapRingHom (Ideal.Quotient.mk q)) (span (map (Ideal.Quotient.mk q) '' {f}))
Module: Mathlib.RingTheory.Ideal.KrullsHeightTheorem

Goal state before:
pp: R : Type u_1
inst✝¹ : CommRing R
inst✝ : IsNoetherianRing R
I : Ideal R
hI : I ≠ ⊤
J : Ideal R
hJ : J ∈ I.minimalPrimes
⊢ I.height ≤ Cardinal.toENat (Submodule.spanRank I)

Tactic:
I.height_eq_inf_minimalPrimes

Goal state after:
R : Type u_1
inst✝¹ : CommRing R
inst✝ : IsNoetherianRing R
I : Ideal R
hI : I ≠ ⊤
J : Ideal R
hJ : J ∈ I.minimalPrimes
⊢ ⨅ J ∈ I.minimalPrimes, J.height ≤ Cardinal.toENat (Submodule.spanRank I)
Module: Mathlib.RingTheory.Ideal.KrullsHeightTheorem

Goal state before:
pp: R : Type u_1
inst✝² : CommRing R
inst✝¹ : IsNoetherianRing R
inst✝ : IsLocalRing R
⊢ ringKrullDim R ≠ ⊥ ∧ ringKrullDim R ≠ ⊤

Tactic:
← IsLocalRing.maximalIdeal_height_eq_ringKrullDim

Goal state after:
R : Type u_1
inst✝² : CommRing R
inst✝¹ : IsNoetherianRing R
inst✝ : IsLocalRing R
⊢ ↑(IsLocalRing.maximalIdeal R).height ≠ ⊥ ∧ ↑(IsLocalRing.maximalIdeal R).height ≠ ⊤
Module: Mathlib.RingTheory.Ideal.KrullsHeightTheorem

Goal state before:
pp: case right
R : Type u_1
inst✝² : CommRing R
inst✝¹ : IsNoetherianRing R
inst✝ : IsLocalRing R
⊢ ↑(IsLocalRing.maximalIdeal R).height ≠ ⊤

Tactic:
rw [← WithBot.coe_top, ne_eq, WithBot.coe_inj]

Goal state after:
case right
R : Type u_1
inst✝² : CommRing R
inst✝¹ : IsNoetherianRing R
inst✝ : IsLocalRing R
⊢ ¬(IsLocalRing.maximalIdeal R).height = ⊤
Module: Mathlib.RingTheory.Ideal.KrullsHeightTheorem

Goal state before:
pp: case refine_2
R : Type u_1
inst✝⁸ : CommRing R
inst✝⁷ : IsNoetherianRing R
S : Type u_2
inst✝⁶ : CommRing S
inst✝⁵ : Algebra R S
inst✝⁴ : IsNoetherianRing S
inst✝³ : Algebra.HasGoingDown R S
p : Ideal R
inst✝² : p.IsPrime
P : Ideal S
inst✝¹ : P.IsPrime
inst✝ : P.LiesOver p
lp : LTSeries (PrimeSpectrum R)
hlp : RelSeries.last lp = { asIdeal := p, isPrime := ⋯ }
hlenp : ↑lp.length = p.height
lq : LTSeries (PrimeSpectrum (S ⧸ map (algebraMap R S) p))
hlq : RelSeries.last lq = { asIdeal := map (Quotient.mk (map (algebraMap R S) p)) P, isPrime := ⋯ }
hlenq : ↑lq.length = (map (Quotient.mk (map (algebraMap R S) p)) P).height
l' : LTSeries (PrimeSpectrum S) := lq.map (PrimeSpectrum.comap (Quotient.mk (map (algebraMap R S) p))) ⋯
⊢ under R (PrimeSpectrum.comap (Quotient.mk (map (algebraMap R S) p)) (RelSeries.head lq)).asIdeal ≤ p

Tactic:
conv_rhs => rw [LiesOver.over (p := p) (P := P), under_def]

Goal state after:
case refine_2
R : Type u_1
inst✝⁸ : CommRing R
inst✝⁷ : IsNoetherianRing R
S : Type u_2
inst✝⁶ : CommRing S
inst✝⁵ : Algebra R S
inst✝⁴ : IsNoetherianRing S
inst✝³ : Algebra.HasGoingDown R S
p : Ideal R
inst✝² : p.IsPrime
P : Ideal S
inst✝¹ : P.IsPrime
inst✝ : P.LiesOver p
lp : LTSeries (PrimeSpectrum R)
hlp : RelSeries.last lp = { asIdeal := p, isPrime := ⋯ }
hlenp : ↑lp.length = p.height
lq : LTSeries (PrimeSpectrum (S ⧸ map (algebraMap R S) p))
hlq : RelSeries.last lq = { asIdeal := map (Quotient.mk (map (algebraMap R S) p)) P, isPrime := ⋯ }
hlenq : ↑lq.length = (map (Quotient.mk (map (algebraMap R S) p)) P).height
l' : LTSeries (PrimeSpectrum S) := lq.map (PrimeSpectrum.comap (Quotient.mk (map (algebraMap R S) p))) ⋯
⊢ under R (PrimeSpectrum.comap (Quotient.mk (map (algebraMap R S) p)) (RelSeries.head lq)).asIdeal ≤
    comap (algebraMap R S) P
Module: Mathlib.RingTheory.Invariant.Profinite

Goal state before:
pp: A : Type u_1
B : Type u_2
inst✝¹⁵ : CommRing A
inst✝¹⁴ : CommRing B
inst✝¹³ : Algebra A B
G : Type u
inst✝¹² : Group G
inst✝¹¹ : MulSemiringAction G B
inst✝¹⁰ : SMulCommClass G A B
inst✝⁹ : TopologicalSpace G
inst✝⁸ : CompactSpace G
inst✝⁷ : TotallyDisconnectedSpace G
inst✝⁶ : IsTopologicalGroup G
inst✝⁵ : TopologicalSpace B
inst✝⁴ : DiscreteTopology B
inst✝³ : ContinuousSMul G B
P : Ideal A
Q : Ideal B
inst✝² : Q.IsPrime
inst✝¹ : Q.LiesOver P
inst✝ : Algebra.IsInvariant A B G
σ : (B ⧸ Q) ≃ₐ[A ⧸ P] B ⧸ Q
B' : (G : Type ?u.58) → [inst : Monoid G] → [inst_1 : MulSemiringAction G B] → [SMulCommClass G A B] → Subalgebra A B :=
  FixedPoints.subalgebra A B
s : (j : OpenNormalSubgroup G) → (stabilizerHomSurjectiveAuxFunctor P Q σ).obj j
hs : s ∈ (stabilizerHomSurjectiveAuxFunctor P Q σ).sections
⊢ ∃ a, (stabilizerHom Q P G) a = σ

Tactic:
let a := (ProfiniteGrp.of G).isoLimittoFiniteQuotientFunctor.inv.hom
    ⟨fun N ↦ (s N).1.1, (fun {N N'} f ↦ congr($(hs f).1.1))⟩

Goal state after:
A : Type u_1
B : Type u_2
inst✝¹⁵ : CommRing A
inst✝¹⁴ : CommRing B
inst✝¹³ : Algebra A B
G : Type u
inst✝¹² : Group G
inst✝¹¹ : MulSemiringAction G B
inst✝¹⁰ : SMulCommClass G A B
inst✝⁹ : TopologicalSpace G
inst✝⁸ : CompactSpace G
inst✝⁷ : TotallyDisconnectedSpace G
inst✝⁶ : IsTopologicalGroup G
inst✝⁵ : TopologicalSpace B
inst✝⁴ : DiscreteTopology B
inst✝³ : ContinuousSMul G B
P : Ideal A
Q : Ideal B
inst✝² : Q.IsPrime
inst✝¹ : Q.LiesOver P
inst✝ : Algebra.IsInvariant A B G
σ : (B ⧸ Q) ≃ₐ[A ⧸ P] B ⧸ Q
B' : (G : Type ?u.58) → [inst : Monoid G] → [inst_1 : MulSemiringAction G B] → [SMulCommClass G A B] → Subalgebra A B :=
  FixedPoints.subalgebra A B
s : (j : OpenNormalSubgroup G) → (stabilizerHomSurjectiveAuxFunctor P Q σ).obj j
hs : s ∈ (stabilizerHomSurjectiveAuxFunctor P Q σ).sections
a : ↑(ProfiniteGrp.of G).toProfinite.toTop :=
  (ProfiniteGrp.Hom.hom (ProfiniteGrp.of G).isoLimittoFiniteQuotientFunctor.inv) ⟨fun N ↦ ↑↑(s N), ⋯⟩
⊢ ∃ a, (stabilizerHom Q P G) a = σ
Module: Mathlib.RingTheory.LaurentSeries

Goal state before:
pp: R : Type u_1
inst✝² : Semiring R
V : Type u_2
inst✝¹ : AddCommGroup V
inst✝ : Module R V
k : ℕ
f : V⸨X⸩
n : ℤ
⊢ ((⇑(derivative R))^[k] f).coeff n = (k.factorial • (hasseDeriv R k) f).coeff n

Tactic:
induction k generalizing f with
  | zero => simp
  | succ k ih =>
    rw [Function.iterate_succ, Function.comp_apply, ih, derivative_apply, hasseDeriv_comp,
      Nat.choose_symm_add, Nat.choose_one_right, Nat.factorial, mul_nsmul]

Goal state after:
Module: Mathlib.RingTheory.LaurentSeries

Goal state before:
pp: case neg
K : Type u_2
inst✝ : Field K
d n : ℤ
f g : K⸨X⸩
H : Valued.v (g - f) ≤ exp (-d)
triv : ¬g = f
hn : n < d
⊢ g.coeff n = f.coeff n

Tactic:
apply eq_of_sub_eq_zero

Goal state after:
case neg
K : Type u_2
inst✝ : Field K
d n : ℤ
f g : K⸨X⸩
H : Valued.v (g - f) ≤ exp (-d)
triv : ¬g = f
hn : n < d
⊢ g.coeff n - f.coeff n = 0
Module: Mathlib.RingTheory.MvPolynomial.IrreducibleQuadratic

Goal state before:
pp: n : Type u_1
R : Type u_2
inst✝¹ : CommRing R
c : n →₀ R
inst✝ : IsDomain R
hc : c.support.Nontrivial
h_dvd : ∀ (r : R), (∀ (i : n), r ∣ c i) → IsUnit r
i j : n
⊢ (fun i ↦ Finsupp.single (Sum.inl i) 1 + Finsupp.single (Sum.inr i) 1) i =
      (fun i ↦ Finsupp.single (Sum.inl i) 1 + Finsupp.single (Sum.inr i) 1) j →
    i = j

Tactic:
by simp +contextual [Finsupp.ext_iff, Finsupp.single_apply, ite_eq_iff']

Goal state after:
Module: Mathlib.RingTheory.MvPolynomial.Symmetric.FundamentalTheorem

Goal state before:
pp: case add_single.hD
R : Type u_3
n m : ℕ
inst✝ : CommSemiring R
r : R
hnm : n ≤ m
i : Fin n
b✝ : ℕ
f✝ : Fin n →₀ ℕ
a✝¹ : i ∉ f✝.support
a✝ : b✝ ≠ 0
ih : leadingCoeff (⇑toLex) (esymmAlgHomMonomial (Fin m) f✝ r) = r
⊢ Function.Injective ⇑toLex

pp: case add_single.hadd
R : Type u_3
n m : ℕ
inst✝ : CommSemiring R
r : R
hnm : n ≤ m
i : Fin n
b✝ : ℕ
f✝ : Fin n →₀ ℕ
a✝¹ : i ∉ f✝.support
a✝ : b✝ ≠ 0
ih : leadingCoeff (⇑toLex) (esymmAlgHomMonomial (Fin m) f✝ r) = r
⊢ ∀ (a1 a2 : Fin m →₀ ℕ), toLex (a1 + a2) = toLex a1 + toLex a2

Tactic:
exacts [toLex.injective, toLex_add]

Goal state after:
Module: Mathlib.RingTheory.MvPolynomial.Symmetric.NewtonIdentities

Goal state before:
pp: case inr
σ : Type u_1
R : Type u_2
inst✝² : CommRing R
inst✝¹ : DecidableEq σ
inst✝ : Fintype σ
k : ℕ
t : Finset σ × σ
h : #t.1 ≤ k ∧ (#t.1 = k → t.2 ∈ t.1)
h2 : ∀ (n : ℕ), -(-1) ^ n = (-1) ^ (n + 1)
h1 : t.2 ∉ t.1
⊢ (∏ a ∈ t.1, X a) * (X t.2 ^ (k - #t.1) * - -(-1) ^ #t.1) +
      (∏ a ∈ t.1, X a) * (X t.2 ^ (k - #t.1) * (-1) ^ (#t.1 + 1)) =
    0

Tactic:
h2

Goal state after:
case inr
σ : Type u_1
R : Type u_2
inst✝² : CommRing R
inst✝¹ : DecidableEq σ
inst✝ : Fintype σ
k : ℕ
t : Finset σ × σ
h : #t.1 ≤ k ∧ (#t.1 = k → t.2 ∈ t.1)
h2 : ∀ (n : ℕ), -(-1) ^ n = (-1) ^ (n + 1)
h1 : t.2 ∉ t.1
⊢ (∏ a ∈ t.1, X a) * (X t.2 ^ (k - #t.1) * -(-1) ^ (#t.1 + 1)) +
      (∏ a ∈ t.1, X a) * (X t.2 ^ (k - #t.1) * (-1) ^ (#t.1 + 1)) =
    0
Module: Mathlib.RingTheory.MvPowerSeries.Expand

Goal state before:
pp: σ : Type u_1
R : Type u_3
inst✝ : CommRing R
p : ℕ
hp : p ≠ 0
φ : MvPowerSeries σ R
m : σ →₀ ℕ
i : σ
h : ¬p ∣ m i
⊢ (coeff m) ((expand p hp) φ) = 0

Tactic:
contrapose! h
  simp only [expand, substAlgHom_apply, coeff_subst (HasSubst.X_pow hp)] at h
  obtain ⟨d, hd⟩ : ∃ (d : σ →₀ ℕ), (coeff m) (d.prod fun s e ↦ ((X s (R := R)) ^ p) ^ e) ≠ 0 := by
    by_contra! hc
    rw [finsum_eq_zero_of_forall_eq_zero fun d => by simp [hc d]] at h
    contradiction
  have : (d.prod fun s e ↦ ((X s (R := R)) ^ p) ^ e) = monomial (p • d) 1 := by
    simp [monomial_smul_eq]
  rw [this, coeff_monomial] at hd
  have meq : m = p • d := by
    by_contra hc
    rw [if_neg hc] at hd
    contradiction
  simp [meq]

Goal state after:
Module: Mathlib.RingTheory.MvPowerSeries.Expand

Goal state before:
pp: σ : Type u_1
R : Type u_3
inst✝¹ : CommRing R
p : ℕ
hp : p ≠ 0
inst✝ : ExpChar R p
f : MvPowerSeries σ R
⊢ (map (frobenius R p)) ((expand p hp) f) = f ^ p

Tactic:
classical
  rw [eq_iff_frequently_trunc'_eq, Filter.frequently_atTop]
  intro n
  use (p • n)
  refine ⟨le_self_nsmul zero_le hp, ?_⟩
  · have : (((trunc' R (p • n) f).expand p).map (frobenius R p)).toMvPowerSeries =
      MvPowerSeries.map (frobenius R p) ((trunc' R (p • n) f).expand p) := by
      simp only [MvPolynomial.map_expand, ← expand_eq_expand p hp, map_expand]
      congr
    rw [trunc'_map, trunc'_expand, ← trunc'_trunc'_pow (Nat.one_le_iff_ne_zero.mpr
      (expChar_ne_zero R p)), ← MvPolynomial.coe_pow p, ← MvPolynomial.map_frobenius_expand, this,
        trunc'_map, trunc'_expand_trunc' p hp (le_self_nsmul zero_le hp)]

Goal state after:
Module: Mathlib.RingTheory.NoetherNormalization

Goal state before:
pp: k : Type u_1
inst✝ : Field k
n : ℕ
f : MvPolynomial (Fin (n + 1)) k
v w : Fin (n + 1) →₀ ℕ
I : Ideal (MvPolynomial (Fin (n + 1)) k)
⊢ Ideal.map ((T f).symm.toRingEquiv.toRingHom.comp ↑(T f)) I = Ideal.map (↑(T f).symm) (Ideal.map (T f) I)

Tactic:
rw [← Ideal.map_map, Ideal.map_coe, Ideal.map_coe]

Goal state after:
k : Type u_1
inst✝ : Field k
n : ℕ
f : MvPolynomial (Fin (n + 1)) k
v w : Fin (n + 1) →₀ ℕ
I : Ideal (MvPolynomial (Fin (n + 1)) k)
⊢ Ideal.map (T f).symm.toRingEquiv.toRingHom (Ideal.map (T f) I) = Ideal.map (T f).symm (Ideal.map (T f) I)
Module: Mathlib.RingTheory.WittVector.StructurePolynomial

Goal state before:
pp: p : ℕ
idx : Type u_2
hp : Fact (Nat.Prime p)
Φ : MvPolynomial idx ℚ
n : ℕ
this : xInTermsOfW p ℚ n * C (↑p ^ n) = X n - ∑ i ∈ Finset.range n, C (↑p ^ i) * xInTermsOfW p ℚ i ^ p ^ (n - i)
⊢ wittStructureRat p Φ n * C (↑p ^ n) =
    (bind₁ fun b ↦ (rename fun i ↦ (b, i)) (W_ ℚ n)) Φ -
      ∑ i ∈ Finset.range n, C (↑p ^ i) * wittStructureRat p Φ i ^ p ^ (n - i)

Tactic:
replace := congr_arg (bind₁ fun k : ℕ => bind₁ (fun i => rename (Prod.mk i) (W_ ℚ k)) Φ) this

Goal state after:
p : ℕ
idx : Type u_2
hp : Fact (Nat.Prime p)
Φ : MvPolynomial idx ℚ
n : ℕ
this :
  (bind₁ fun k ↦ (bind₁ fun i ↦ (rename (Prod.mk i)) (W_ ℚ k)) Φ) (xInTermsOfW p ℚ n * C (↑p ^ n)) =
    (bind₁ fun k ↦ (bind₁ fun i ↦ (rename (Prod.mk i)) (W_ ℚ k)) Φ)
      (X n - ∑ i ∈ Finset.range n, C (↑p ^ i) * xInTermsOfW p ℚ i ^ p ^ (n - i))
⊢ wittStructureRat p Φ n * C (↑p ^ n) =
    (bind₁ fun b ↦ (rename fun i ↦ (b, i)) (W_ ℚ n)) Φ -
      ∑ i ∈ Finset.range n, C (↑p ^ i) * wittStructureRat p Φ i ^ p ^ (n - i)
Module: Mathlib.RingTheory.WittVector.Defs

Goal state before:
pp: p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝ : CommRing R
x y : 𝕎 R
n : ℕ
⊢ (x - y).coeff n = peval (wittSub p n) ![x.coeff, y.coeff]

Tactic:
simp [(· - ·), Sub.sub, eval]

Goal state after:
Module: Mathlib.RingTheory.WittVector.Basic

Goal state before:
pp: p : ℕ
R : Type u_1
inst✝¹ : CommRing R
inst✝ : Fact (Nat.Prime p)
⊢ ghostFun 1 = 1

Tactic:
ghost_fun_tac 1, ![]

Goal state after:
Module: Mathlib.RingTheory.WittVector.StructurePolynomial

Goal state before:
pp: case h.hn
p : ℕ
idx : Type u_2
hp : Fact (Nat.Prime p)
Φ : MvPolynomial idx ℤ
n : ℕ
IH : ∀ m < n, (map (Int.castRingHom ℚ)) (wittStructureInt p Φ m) = wittStructureRat p ((map (Int.castRingHom ℚ)) Φ) m
c : idx × ℕ →₀ ℕ
sum_induction_steps :
  (map (Int.castRingHom ℚ)) (∑ i ∈ Finset.range n, C (↑p ^ i) * wittStructureInt p Φ i ^ p ^ (n - i)) =
    ∑ i ∈ Finset.range n, C (↑p ^ i) * wittStructureRat p ((map (Int.castRingHom ℚ)) Φ) i ^ p ^ (n - i)
⊢ ↑(p ^ n) ≠ 0

Tactic:
exact mod_cast pow_ne_zero n hp.1.ne_zero

Goal state after:
Module: Mathlib.RingTheory.WittVector.Identities

Goal state before:
pp: case calc_2
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i] (x * (⇑frobenius)^[i] ((⇑verschiebung)^[j] y)) =
    (⇑verschiebung)^[i] (x * (⇑verschiebung)^[j] ((⇑frobenius)^[i] y))

pp: case calc_3
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i] (x * (⇑verschiebung)^[j] ((⇑frobenius)^[i] y)) =
    (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y) * x)

pp: case calc_4
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y) * x) =
    (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x))

pp: case calc_5
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x)) =
    (⇑verschiebung)^[i + j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x)

pp: case calc_6
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i + j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x) =
    (⇑verschiebung)^[i + j] ((⇑frobenius)^[j] x * (⇑frobenius)^[i] y)

Tactic:
· rw [verschiebung_frobenius_comm.iterate_iterate]

Goal state after:
case calc_3
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i] (x * (⇑verschiebung)^[j] ((⇑frobenius)^[i] y)) =
    (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y) * x)

case calc_4
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y) * x) =
    (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x))

case calc_5
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i] ((⇑verschiebung)^[j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x)) =
    (⇑verschiebung)^[i + j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x)

case calc_6
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ (⇑verschiebung)^[i + j] ((⇑frobenius)^[i] y * (⇑frobenius)^[j] x) =
    (⇑verschiebung)^[i + j] ((⇑frobenius)^[j] x * (⇑frobenius)^[i] y)
Module: Mathlib.RingTheory.WittVector.Identities

Goal state before:
pp: case calc_4
p : ℕ
R : Type u_1
hp : Fact (Nat.Prime p)
inst✝¹ : CommRing R
inst✝ : CharP R p
x y : 𝕎 R
i j : ℕ
⊢ ((⇑frobenius)^[j] x).coeff 0 * ((⇑frobenius)^[i] y).coeff 0 = x.coeff 0 ^ p ^ j * y.coeff 0 ^ p ^ i

Tactic:
simp only [iterate_frobenius_coeff]

Goal state after:
Module: Mathlib.RingTheory.WittVector.InitTail

Goal state before:
pp: case refine_3
p : ℕ
P : ℕ → Prop
hp : Fact (Nat.Prime p)
this : IsPoly p fun {R} [CommRing R] x ↦ select P x + select (fun i ↦ ¬P i) x
R : Type u_1
R._inst : CommRing R
x : 𝕎 R
n m : ℕ
x✝ : m ∈ Finset.range (n + 1)
⊢ (if P m then X m else 0) ^ p ^ (n - m) + (if ¬P m then X m else 0) ^ p ^ (n - m) = X m ^ p ^ (n - m)

Tactic:
ite_pow,

Goal state after:
case refine_3
p : ℕ
P : ℕ → Prop
hp : Fact (Nat.Prime p)
this : IsPoly p fun {R} [CommRing R] x ↦ select P x + select (fun i ↦ ¬P i) x
R : Type u_1
R._inst : CommRing R
x : 𝕎 R
n m : ℕ
x✝ : m ∈ Finset.range (n + 1)
⊢ (if P m then X m ^ p ^ (n - m) else 0 ^ p ^ (n - m)) + (if ¬P m then X m else 0) ^ p ^ (n - m) = X m ^ p ^ (n - m)
Module: Mathlib.RingTheory.WittVector.Truncated

Goal state before:
pp: p : ℕ
R : Type u_1
inst✝² : CommRing R
inst✝¹ : Fact (Nat.Prime p)
S : Type u_2
inst✝ : Semiring S
f : (k : ℕ) → S →+* TruncatedWittVector p k R
f_compat : ∀ (k₁ k₂ : ℕ) (hk : k₁ ≤ k₂), (TruncatedWittVector.truncate hk).comp (f k₂) = f k₁
g : S →+* 𝕎 R
g_compat : ∀ (k : ℕ), (truncate k).comp g = f k
⊢ lift f f_compat = g

Tactic:
ext1 x
  rw [← sub_eq_zero, ← Ideal.mem_bot, ← iInf_ker_truncate, Ideal.mem_iInf]
  intro i
  simp only [RingHom.mem_ker, g_compat, ← RingHom.comp_apply, truncate_comp_lift, map_sub, sub_self]

Goal state after:
Module: Mathlib.RingTheory.WittVector.TeichmullerSeries

Goal state before:
pp: case insert
p : ℕ
hp : Fact (Nat.Prime p)
R : Type u_1
inst✝ : CommRing R
α : Type u_2
x : α → 𝕎 R
a : α
S' : Finset α
ha : a ∉ S'
h : ∀ (n : ℕ), Subsingleton ↑{r | r ∈ insert a S' ∧ (x r).coeff n ≠ 0}
n : ℕ
this✝ : ∀ (n : ℕ), Subsingleton ↑{r | r ∈ S' ∧ (x r).coeff n ≠ 0}
hind : ∀ (n : ℕ), (∑ s ∈ S', x s).coeff n = ∑ s ∈ S', (x s).coeff n
this : ∀ (n : ℕ), (x a).coeff n = 0 ∨ (∑ s ∈ S', x s).coeff n = 0
⊢ (x a + ∑ s ∈ S', x s).coeff n = (x a).coeff n + ∑ s ∈ S', (x s).coeff n

Tactic:
rw [coeff_add_of_disjoint n _ _ this, hind n]

Goal state after:
Module: Mathlib.RingTheory.Polynomial.HilbertPoly

Goal state before:
pp: F : Type u_1
inst✝¹ : Field F
inst✝ : CharZero F
d k : ℕ
⊢ (preHilbertPoly F d k).natDegree = d

Tactic:
have hne : (d ! : F) ≠ 0 := by norm_cast; positivity
  rw [preHilbertPoly, natDegree_smul _ (inv_ne_zero hne), natDegree_comp, ascPochhammer_natDegree,
    add_comm_sub, ← C_1, ← map_sub, natDegree_add_C, natDegree_X, mul_one]

Goal state after:
Module: Mathlib.RingTheory.Polynomial.Dickson

Goal state before:
pp: p : ℕ
inst✝ : Fact (Nat.Prime p)
K : Type
w✝¹ : Field K
w✝ : CharP K p
H : Set.univ.Infinite
h : {x | ∃ y, x = y + y⁻¹ ∧ y ≠ 0}.Finite
this : Set.univ = ⋃ x ∈ {x | ∃ y, x = y + y⁻¹ ∧ y ≠ 0}, {y | x = y + y⁻¹ ∨ y = 0}
⊢ Set.univ.Finite

Tactic:
rw [this]
      clear this
      refine h.biUnion fun x _ => ?_
      -- The following quadratic polynomial has as solutions the `y` for which `x = y + y⁻¹`.
      let φ : K[X] := X ^ 2 - C x * X + 1
      have hφ : φ ≠ 0 := by
        intro H
        have : φ.eval 0 = 0 := by rw [H, eval_zero]
        simpa [φ, eval_X, eval_one, eval_pow, eval_sub, sub_zero, eval_add, eval_mul,
          mul_zero, sq, zero_add, one_ne_zero]
      classical
        convert! (φ.roots ∪ {0}).toFinset.finite_toSet using 1
        ext1 y
        simp only [φ, Multiset.mem_toFinset, Set.mem_ofPred_eq, Finset.mem_coe, Multiset.mem_union,
          mem_roots hφ, IsRoot, eval_add, eval_sub, eval_pow, eval_mul, eval_X, eval_C, eval_one,
          Multiset.mem_singleton]
        by_cases hy : y = 0
        · simp only [hy, or_true]
        apply or_congr _ Iff.rfl
        rw [← mul_left_inj' hy, eq_comm, ← sub_eq_zero, add_mul, inv_mul_cancel₀ hy]
        apply eq_iff_eq_cancel_right.mpr
        ring

Goal state after:
Module: Mathlib.RingTheory.Polynomial.Dickson

Goal state before:
pp: R : Type u_1
inst✝² : CommRing R
p : ℕ
inst✝¹ : Fact (Nat.Prime p)
inst✝ : CharP R p
⊢ 1 = (ZMod.castHom ⋯ R) 1

Tactic:
simp only [ZMod.castHom_apply, ZMod.cast_one']

Goal state after: