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one_add_α_pow_q_succ [Fact q.Prime] (odd : Odd q) (leg3 : legendreSym q 3 = -1) : (1 + α : X q) ^ (q + 1) = -2 := by rw [pow_succ, one_add_α_pow_q odd leg3, mul_comm, ← _root_.sq_sub_sq, α_sq] norm_num
lemma
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
one_add_α_pow_q_succ
If `3` is not a square then `(1 + α) ^ (q + 1) = -2`.
two_mul_ω_pow [Fact q.Prime] (odd : Odd q) (leg3 : legendreSym q 3 = -1) : (2 * ω : X q) ^ ((q + 1) / 2) = -2 := by rw [← one_add_α_sq, ← pow_mul] have : 2 * ((q + 1) / 2) = q + 1 := by apply Nat.mul_div_cancel' rw [← even_iff_two_dvd] exact Odd.add_one odd rw [this, one_add_α_pow_q_succ odd leg3]
lemma
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
two_mul_ω_pow
If `3` is not a square then `(2 * ω) ^ ((q + 1) / 2) = -2`.
pow_ω [Fact q.Prime] (odd : Odd q) (leg3 : legendreSym q 3 = -1) (leg2 : legendreSym q 2 = 1) : (ω : X q) ^ ((q + 1) / 2) = -1 := by have pow2 : (2 : ZMod q) ^ ((q + 1) / 2) = 2 := by obtain ⟨_, _⟩ := odd rw [(by cutsat : (q + 1) / 2 = q / 2 + 1), pow_succ] have leg := legendreSym.eq_pow q 2 ...
lemma
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
pow_ω
If 3 is not a square and 2 is square then $\omega^{(q+1)/2}=-1$.
ω_pow_trace [Fact q.Prime] (odd : Odd q) (leg3 : legendreSym q 3 = -1) (leg2 : legendreSym q 2 = 1) (hq4 : 4 ∣ q + 1) : (ω : X q) ^ ((q + 1) / 4) + ωb ^ ((q + 1) / 4) = 0 := by have : (ω : X q) ^ ((q + 1) / 2) * ωb ^ ((q + 1) / 4) = -ωb ^ ((q + 1) / 4) := by rw [pow_ω odd leg3 leg2] ring hav...
lemma
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
ω_pow_trace
The final evaluation needed to establish the Lucas-Lehmer necessity.
card_eq : Fintype.card (X q) = q ^ 2 := by dsimp [X] rw [Fintype.card_prod, ZMod.card q, sq]
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
card_eq
The cardinality of `X` is `q^2`.
two_lt_q (p' : ℕ) : 2 < q (p' + 2) := by refine (minFac_prime (one_lt_mersenne.2 ?_).ne').two_le.lt_of_ne' ?_ · exact le_add_left _ _ · rw [Ne, minFac_eq_two_iff, mersenne, Nat.pow_succ'] exact Nat.two_not_dvd_two_mul_sub_one Nat.one_le_two_pow
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
two_lt_q
There are strictly fewer than `q^2` units, since `0` is not a unit. -/ nonrec theorem card_units_lt (w : 1 < q) : Fintype.card (X q)ˣ < q ^ 2 := by have : Fact (1 < (q : ℕ)) := ⟨w⟩ convert card_units_lt (X q) rw [card_eq] end X open X /-! Here and below, we introduce `p' = p - 2`, in order to avoid using subtr...
ω_pow_formula (p' : ℕ) (h : lucasLehmerResidue (p' + 2) = 0) : ∃ k : ℤ, (ω : X (q (p' + 2))) ^ 2 ^ (p' + 1) = k * mersenne (p' + 2) * (ω : X (q (p' + 2))) ^ 2 ^ p' - 1 := by dsimp [lucasLehmerResidue] at h rw [sZMod_eq_s p'] at h replace h : 2 ^ (p' + 2) - 1 ∣ s p' := by simpa [ZMod.intCast_zmod...
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
ω_pow_formula
null
mersenne_coe_X (p : ℕ) : (mersenne p : X (q p)) = 0 := by ext <;> simp [mersenne, q, ZMod.natCast_eq_zero_iff, -pow_pos] apply Nat.minFac_dvd
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
mersenne_coe_X
`q` is the minimum factor of `mersenne p`, so `M p = 0` in `X q`.
ω_pow_eq_neg_one (p' : ℕ) (h : lucasLehmerResidue (p' + 2) = 0) : (ω : X (q (p' + 2))) ^ 2 ^ (p' + 1) = -1 := by obtain ⟨k, w⟩ := ω_pow_formula p' h rw [mersenne_coe_X] at w simpa using w
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
ω_pow_eq_neg_one
null
ω_pow_eq_one (p' : ℕ) (h : lucasLehmerResidue (p' + 2) = 0) : (ω : X (q (p' + 2))) ^ 2 ^ (p' + 2) = 1 := calc (ω : X (q (p' + 2))) ^ 2 ^ (p' + 2) = (ω ^ 2 ^ (p' + 1)) ^ 2 := by rw [← pow_mul, ← Nat.pow_succ] _ = (-1) ^ 2 := by rw [ω_pow_eq_neg_one p' h] _ = 1 := by simp
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
ω_pow_eq_one
null
ωUnit (p : ℕ) : Units (X (q p)) where val := ω inv := ωb val_inv := ω_mul_ωb inv_val := ωb_mul_ω @[simp]
def
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
ωUnit
`ω` as an element of the group of units.
ωUnit_coe (p : ℕ) : (ωUnit p : X (q p)) = ω := rfl
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
ωUnit_coe
null
order_ω (p' : ℕ) (h : lucasLehmerResidue (p' + 2) = 0) : orderOf (ωUnit (p' + 2)) = 2 ^ (p' + 2) := by apply Nat.eq_prime_pow_of_dvd_least_prime_pow · exact Nat.prime_two · intro o have ω_pow := congr_arg (Units.coeHom (X (q (p' + 2))) : Units (X (q (p' + 2))) → X (q (p' + 2))) <| orderOf_dv...
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
order_ω
The order of `ω` in the unit group is exactly `2^p`.
order_ineq (p' : ℕ) (h : lucasLehmerResidue (p' + 2) = 0) : 2 ^ (p' + 2) < (q (p' + 2) : ℕ) ^ 2 := calc 2 ^ (p' + 2) = orderOf (ωUnit (p' + 2)) := (order_ω p' h).symm _ ≤ Fintype.card (X (q (p' + 2)))ˣ := orderOf_le_card_univ _ < q (p' + 2) ^ 2 := card_units_lt (Nat.lt_of_succ_lt (two_lt_q _))
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
order_ineq
null
lucas_lehmer_sufficiency (p : ℕ) (w : 1 < p) : LucasLehmerTest p → (mersenne p).Prime := by set p' := p - 2 with hp' clear_value p' obtain rfl : p = p' + 2 := by cutsat have w : 1 < p' + 2 := Nat.lt_of_sub_eq_succ rfl contrapose intro a t have h₁ := order_ineq p' t have h₂ := Nat.minFac_sq_le_self (mers...
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
lucas_lehmer_sufficiency
null
lucas_lehmer_necessity (p : ℕ) (w : 3 ≤ p) (hp : (mersenne p).Prime) : LucasLehmerTest p := by have : Fact (mersenne p).Prime := ⟨‹_›⟩ set p' := p - 2 with hp' clear_value p' obtain rfl : p = p' + 2 := by cutsat dsimp [LucasLehmerTest, lucasLehmerResidue] rw [sZMod_eq_s p', ← X.fst_intCast, X.closed_for...
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
lucas_lehmer_necessity
If `2^p-1` is prime then the Lucas-Lehmer test holds, `s(p-2) % (2^p-1) = 0.
sModNat (q : ℕ) : ℕ → ℕ | 0 => 4 % q | i + 1 => (sModNat q i ^ 2 + (q - 2)) % q
def
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
sModNat
Version of `sMod` that is `ℕ`-valued. One should have `q = 2 ^ p - 1`. This can be reduced by the kernel.
sModNat_eq_sMod (p k : ℕ) (hp : 2 ≤ p) : (sModNat (2 ^ p - 1) k : ℤ) = sMod p k := by have h1 := calc 4 = 2 ^ 2 := by simp _ ≤ 2 ^ p := Nat.pow_le_pow_right (by simp) hp have h2 : 1 ≤ 2 ^ p := by omega induction k with | zero => rw [sModNat, sMod, Int.natCast_emod] simp [h2] | succ k ih => ...
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
sModNat_eq_sMod
null
sModNatTR (q k : ℕ) : ℕ := go k (4 % q) where /-- Helper function for `sMod''`. -/ go : ℕ → ℕ → ℕ | 0, acc => acc | n + 1, acc => go n ((acc ^ 2 + (q - 2)) % q)
def
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
sModNatTR
Tail-recursive version of `sModNat`.
sModNat_aux (b q : ℕ) : ℕ → ℕ | 0 => b | i + 1 => (sModNat_aux b q i ^ 2 + (q - 2)) % q
def
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
sModNat_aux
Generalization of `sModNat` with arbitrary base case, useful for proving `sModNatTR` and `sModNat` agree.
sModNat_aux_eq (q k : ℕ) : sModNat_aux (4 % q) q k = sModNat q k := by induction k with | zero => rfl | succ k ih => rw [sModNat_aux, ih, sModNat, ← ih]
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
sModNat_aux_eq
null
sModNatTR_eq_sModNat (q i : ℕ) : sModNatTR q i = sModNat q i := by rw [sModNatTR, helper, sModNat_aux_eq] where helper b q k : sModNatTR.go q k b = sModNat_aux b q k := by induction k generalizing b with | zero => rfl | succ k ih => rw [sModNatTR.go, ih, sModNat_aux] clear ih induction...
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
sModNatTR_eq_sModNat
null
testTrueHelper (p : ℕ) (hp : Nat.blt 1 p = true) (h : sModNatTR (2 ^ p - 1) (p - 2) = 0) : LucasLehmerTest p := by rw [Nat.blt_eq] at hp rw [LucasLehmerTest, LucasLehmer.residue_eq_zero_iff_sMod_eq_zero p hp, ← sModNat_eq_sMod p _ hp, ← sModNatTR_eq_sModNat, h] rfl
lemma
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
testTrueHelper
null
testFalseHelper (p : ℕ) (hp : Nat.blt 1 p = true) (h : Nat.ble 1 (sModNatTR (2 ^ p - 1) (p - 2))) : ¬ LucasLehmerTest p := by rw [Nat.blt_eq] at hp rw [Nat.ble_eq, Nat.succ_le, Nat.pos_iff_ne_zero] at h rw [LucasLehmerTest, LucasLehmer.residue_eq_zero_iff_sMod_eq_zero p hp, ← sModNat_eq_sMod p _ hp, ← sMo...
lemma
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
testFalseHelper
null
isNat_lucasLehmerTest : {p np : ℕ} → IsNat p np → LucasLehmerTest np → LucasLehmerTest p | _, _, ⟨rfl⟩, h => h
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
isNat_lucasLehmerTest
null
isNat_not_lucasLehmerTest : {p np : ℕ} → IsNat p np → ¬ LucasLehmerTest np → ¬ LucasLehmerTest p | _, _, ⟨rfl⟩, h => h
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
isNat_not_lucasLehmerTest
null
@[norm_num LucasLehmer.LucasLehmerTest (_ : ℕ)] evalLucasLehmerTest : NormNumExt where eval {_ _} e := do let .app _ (p : Q(ℕ)) ← Meta.whnfR e | failure let ⟨ep, hp⟩ ← deriveNat p _ let np := ep.natLit! unless 1 < np do failure haveI' h1ltp : Nat.blt 1 $ep =Q true := ⟨⟩ if sModNatTR (2 ^ np - 1) (np - 2...
def
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
evalLucasLehmerTest
Calculate `LucasLehmer.LucasLehmerTest p` for `2 ≤ p` by using kernel reduction for the `sMod'` function.
modEq_mersenne (n k : ℕ) : k ≡ k / 2 ^ n + k % 2 ^ n [MOD 2 ^ n - 1] := calc k = 2 ^ n * (k / 2 ^ n) + k % 2 ^ n := (Nat.div_add_mod k (2 ^ n)).symm _ ≡ 1 * (k / 2 ^ n) + k % 2 ^ n [MOD 2 ^ n - 1] := ((Nat.modEq_sub <| Nat.succ_le_of_lt <| pow_pos zero_lt_two _).mul_right _).add_right _ _ = k / 2 ^ ...
theorem
NumberTheory
[ "Mathlib.NumberTheory.Fermat", "Mathlib.RingTheory.Fintype" ]
Mathlib/NumberTheory/LucasLehmer.lean
modEq_mersenne
null
lucas_primality (p : ℕ) (a : ZMod p) (ha : a ^ (p - 1) = 1) (hd : ∀ q : ℕ, q.Prime → q ∣ p - 1 → a ^ ((p - 1) / q) ≠ 1) : p.Prime := by have h : p ≠ 0 ∧ p ≠ 1 := by constructor <;> rintro rfl <;> exact hd 2 Nat.prime_two (dvd_zero _) (pow_zero _) have hp1 : 1 < p := Nat.one_lt_iff_ne_zero_and_ne_one.2 h h...
theorem
NumberTheory
[ "Mathlib.Algebra.Field.ZMod", "Mathlib.RingTheory.IntegralDomain" ]
Mathlib/NumberTheory/LucasPrimality.lean
lucas_primality
If `a^(p-1) = 1 mod p`, but `a^((p-1)/q) ≠ 1 mod p` for all prime factors `q` of `p-1`, then `p` is prime. This is true because `a` has order `p-1` in the multiplicative group mod `p`, so this group must itself have order `p-1`, which only happens when `p` is prime.
reverse_lucas_primality (p : ℕ) (hP : p.Prime) : ∃ a : ZMod p, a ^ (p - 1) = 1 ∧ ∀ q : ℕ, q.Prime → q ∣ p - 1 → a ^ ((p - 1) / q) ≠ 1 := by have : Fact p.Prime := ⟨hP⟩ obtain ⟨g, hg⟩ := IsCyclic.exists_generator (α := (ZMod p)ˣ) have h1 : orderOf g = p - 1 := by rwa [orderOf_eq_card_of_forall_mem_zpowers ...
theorem
NumberTheory
[ "Mathlib.Algebra.Field.ZMod", "Mathlib.RingTheory.IntegralDomain" ]
Mathlib/NumberTheory/LucasPrimality.lean
reverse_lucas_primality
If `p` is prime, then there exists an `a` such that `a^(p-1) = 1 mod p` and `a^((p-1)/q) ≠ 1 mod p` for all prime factors `q` of `p-1`. The multiplicative group mod `p` is cyclic, so `a` can be any generator of the group (which must have order `p-1`).
lucas_primality_iff (p : ℕ) : p.Prime ↔ ∃ a : ZMod p, a ^ (p - 1) = 1 ∧ ∀ q : ℕ, q.Prime → q ∣ p - 1 → a ^ ((p - 1) / q) ≠ 1 := ⟨reverse_lucas_primality p, fun ⟨a, ⟨ha, hb⟩⟩ ↦ lucas_primality p a ha hb⟩
theorem
NumberTheory
[ "Mathlib.Algebra.Field.ZMod", "Mathlib.RingTheory.IntegralDomain" ]
Mathlib/NumberTheory/LucasPrimality.lean
lucas_primality_iff
A number `p` is prime if and only if there exists an `a` such that `a^(p-1) = 1 mod p` and `a^((p-1)/q) ≠ 1 mod p` for all prime factors `q` of `p-1`.
GrahamConjecture (n : ℕ) (f : ℕ → ℕ) : Prop := n ≠ 0 → StrictMonoOn f (Set.Iio n) → ∃ i < n, ∃ j < n, (f i).gcd (f j) * n ≤ f i
def
NumberTheory
[ "Mathlib.Combinatorics.SetFamily.FourFunctions", "Mathlib.Data.Nat.Squarefree" ]
Mathlib/NumberTheory/MaricaSchoenheim.lean
GrahamConjecture
Statement of Graham's conjecture (which is now a theorem in the literature). Graham's conjecture states that if $0 < a_1 < \dots a_n$ are integers, then $\max_{i, j} \frac{a_i}{\gcd(a_i, a_j)} \ge n$.
grahamConjecture_of_squarefree {n : ℕ} (f : ℕ → ℕ) (hf' : ∀ k < n, Squarefree (f k)) : GrahamConjecture n f := by rintro hn hf by_contra! set 𝒜 := (Iio n).image fun n ↦ primeFactors (f n) have hf'' : ∀ i < n, ∀ j, Squarefree (f i / (f i).gcd (f j)) := fun i hi j ↦ (hf' _ hi).squarefree_of_dvd <| div_dv...
lemma
NumberTheory
[ "Mathlib.Combinatorics.SetFamily.FourFunctions", "Mathlib.Data.Nat.Squarefree" ]
Mathlib/NumberTheory/MaricaSchoenheim.lean
grahamConjecture_of_squarefree
The special case of Graham's conjecture where all numbers are squarefree.
bottom_row_coprime {R : Type*} [CommRing R] (g : SL(2, R)) : IsCoprime ((↑g : Matrix (Fin 2) (Fin 2) R) 1 0) ((↑g : Matrix (Fin 2) (Fin 2) R) 1 1) := isCoprime_row g 1
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
bottom_row_coprime
The two numbers `c`, `d` in the "bottom_row" of `g=[[*,*],[c,d]]` in `SL(2, ℤ)` are coprime.
bottom_row_surj {R : Type*} [CommRing R] : Set.SurjOn (fun g : SL(2, R) => (↑g : Matrix (Fin 2) (Fin 2) R) 1) Set.univ {cd | IsCoprime (cd 0) (cd 1)} := by rintro cd ⟨b₀, a, gcd_eqn⟩ let A := of ![![a, -b₀], cd] have det_A_1 : det A = 1 := by convert gcd_eqn rw [det_fin_two] simp [A, (by rin...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
bottom_row_surj
Every pair `![c, d]` of coprime integers is the "bottom_row" of some element `g=[[*,*],[c,d]]` of `SL(2,ℤ)`.
tendsto_normSq_coprime_pair : Filter.Tendsto (fun p : Fin 2 → ℤ => normSq ((p 0 : ℂ) * z + p 1)) cofinite atTop := by letI : Module ℝ (Fin 2 → ℝ) := NormedSpace.toModule let π₀ : (Fin 2 → ℝ) →ₗ[ℝ] ℝ := LinearMap.proj 0 let π₁ : (Fin 2 → ℝ) →ₗ[ℝ] ℝ := LinearMap.proj 1 let f : (Fin 2 → ℝ) →ₗ[ℝ] ℂ := π₀.smulRi...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
tendsto_normSq_coprime_pair
The function `(c,d) → |cz+d|^2` is proper, that is, preimages of bounded-above sets are finite.
lcRow0 (p : Fin 2 → ℤ) : Matrix (Fin 2) (Fin 2) ℝ →ₗ[ℝ] ℝ := ((p 0 : ℝ) • LinearMap.proj (0 : Fin 2) + (p 1 : ℝ) • LinearMap.proj (1 : Fin 2) : (Fin 2 → ℝ) →ₗ[ℝ] ℝ).comp (LinearMap.proj 0) @[simp]
def
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
lcRow0
Given `coprime_pair` `p=(c,d)`, the matrix `[[a,b],[*,*]]` is sent to `a*c+b*d`. This is the linear map version of this operation.
lcRow0_apply (p : Fin 2 → ℤ) (g : Matrix (Fin 2) (Fin 2) ℝ) : lcRow0 p g = p 0 * g 0 0 + p 1 * g 0 1 := rfl
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
lcRow0_apply
null
@[simps!] lcRow0Extend {cd : Fin 2 → ℤ} (hcd : IsCoprime (cd 0) (cd 1)) : Matrix (Fin 2) (Fin 2) ℝ ≃ₗ[ℝ] Matrix (Fin 2) (Fin 2) ℝ := LinearEquiv.piCongrRight ![by refine LinearMap.GeneralLinearGroup.generalLinearEquiv ℝ (Fin 2 → ℝ) (GeneralLinearGroup.toLin (planeConformalMatrix (cd 0 ...
def
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
lcRow0Extend
Linear map sending the matrix [a, b; c, d] to the matrix [ac₀ + bd₀, - ad₀ + bc₀; c, d], for some fixed `(c₀, d₀)`.
tendsto_lcRow0 {cd : Fin 2 → ℤ} (hcd : IsCoprime (cd 0) (cd 1)) : Tendsto (fun g : { g : SL(2, ℤ) // g 1 = cd } => lcRow0 cd ↑(↑g : SL(2, ℝ))) cofinite (cocompact ℝ) := by let mB : ℝ → Matrix (Fin 2) (Fin 2) ℝ := fun t => of ![![t, (-(1 : ℤ) : ℝ)], (↑) ∘ cd] have hmB : Continuous mB := by refine conti...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
tendsto_lcRow0
The map `lcRow0` is proper, that is, preimages of cocompact sets are finite in `[[* , *], [c, d]]`.
smul_eq_lcRow0_add {p : Fin 2 → ℤ} (hp : IsCoprime (p 0) (p 1)) (hg : g 1 = p) : ↑(g • z) = (lcRow0 p ↑(g : SL(2, ℝ)) : ℂ) / ((p 0 : ℂ) ^ 2 + (p 1 : ℂ) ^ 2) + ((p 1 : ℂ) * z - p 0) / (((p 0 : ℂ) ^ 2 + (p 1 : ℂ) ^ 2) * (p 0 * z + p 1)) := by have nonZ1 : (p 0 : ℂ) ^ 2 + (p 1 : ℂ) ^ 2 ≠ 0 := mod_cast ...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
smul_eq_lcRow0_add
This replaces `(g•z).re = a/c + *` in the standard theory with the following novel identity: `g • z = (a c + b d) / (c^2 + d^2) + (d z - c) / ((c^2 + d^2) (c z + d))` which does not need to be decomposed depending on whether `c = 0`.
tendsto_abs_re_smul {p : Fin 2 → ℤ} (hp : IsCoprime (p 0) (p 1)) : Tendsto (fun g : { g : SL(2, ℤ) // g 1 = p } => |((g : SL(2, ℤ)) • z).re|) cofinite atTop := by suffices Tendsto (fun g : (fun g : SL(2, ℤ) => g 1) ⁻¹' {p} => ((g : SL(2, ℤ)) • z).re) cofinite (cocompact ℝ) by exact tendsto_nor...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
tendsto_abs_re_smul
null
exists_max_im : ∃ g : SL(2, ℤ), ∀ g' : SL(2, ℤ), (g' • z).im ≤ (g • z).im := by classical let s : Set (Fin 2 → ℤ) := {cd | IsCoprime (cd 0) (cd 1)} have hs : s.Nonempty := ⟨![1, 1], isCoprime_one_left⟩ obtain ⟨p, hp_coprime, hp⟩ := Filter.Tendsto.exists_within_forall_le hs (tendsto_normSq_coprime_pair z) ...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
exists_max_im
For `z : ℍ`, there is a `g : SL(2,ℤ)` maximizing `(g•z).im`
exists_row_one_eq_and_min_re {cd : Fin 2 → ℤ} (hcd : IsCoprime (cd 0) (cd 1)) : ∃ g : SL(2, ℤ), g 1 = cd ∧ ∀ g' : SL(2, ℤ), g 1 = g' 1 → |(g • z).re| ≤ |(g' • z).re| := by haveI : Nonempty { g : SL(2, ℤ) // g 1 = cd } := let ⟨x, hx⟩ := bottom_row_surj hcd ⟨⟨x, hx.2⟩⟩ obtain ⟨g, hg⟩ := Filter.Tends...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
exists_row_one_eq_and_min_re
Given `z : ℍ` and a bottom row `(c,d)`, among the `g : SL(2,ℤ)` with this bottom row, minimize `|(g•z).re|`.
coe_T_zpow_smul_eq {n : ℤ} : (↑(T ^ n • z) : ℂ) = z + n := by rw [UpperHalfPlane.coe_specialLinearGroup_apply] simp [coe_T_zpow, -map_zpow]
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
coe_T_zpow_smul_eq
null
re_T_zpow_smul (n : ℤ) : (T ^ n • z).re = z.re + n := by rw [← coe_re, coe_T_zpow_smul_eq, add_re, intCast_re, coe_re]
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
re_T_zpow_smul
null
im_T_zpow_smul (n : ℤ) : (T ^ n • z).im = z.im := by rw [← coe_im, coe_T_zpow_smul_eq, add_im, intCast_im, add_zero, coe_im]
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
im_T_zpow_smul
null
re_T_smul : (T • z).re = z.re + 1 := by simpa using re_T_zpow_smul z 1
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
re_T_smul
null
im_T_smul : (T • z).im = z.im := by simpa using im_T_zpow_smul z 1
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
im_T_smul
null
re_T_inv_smul : (T⁻¹ • z).re = z.re - 1 := by simpa using re_T_zpow_smul z (-1)
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
re_T_inv_smul
null
im_T_inv_smul : (T⁻¹ • z).im = z.im := by simpa using im_T_zpow_smul z (-1) variable {z}
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
im_T_inv_smul
null
exists_eq_T_zpow_of_c_eq_zero (hc : g 1 0 = 0) : ∃ n : ℤ, ∀ z : ℍ, g • z = T ^ n • z := by have had := g.det_coe replace had : g 0 0 * g 1 1 = 1 := by rw [det_fin_two, hc] at had; omega rcases Int.eq_one_or_neg_one_of_mul_eq_one' had with (⟨ha, hd⟩ | ⟨ha, hd⟩) · use g 0 1 suffices g = T ^ g 0 1 by intro...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
exists_eq_T_zpow_of_c_eq_zero
null
g_eq_of_c_eq_one (hc : g 1 0 = 1) : g = T ^ g 0 0 * S * T ^ g 1 1 := by have hg := g.det_coe.symm replace hg : g 0 1 = g 0 0 * g 1 1 - 1 := by rw [det_fin_two, hc] at hg; omega refine Subtype.ext ?_ conv_lhs => rw [(g : Matrix _ _ ℤ).eta_fin_two] simp only [hg, sub_eq_add_neg, hc, coe_mul, coe_T_zpow, coe_S, ...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
g_eq_of_c_eq_one
null
normSq_S_smul_lt_one (h : 1 < normSq z) : normSq ↑(S • z) < 1 := by rw [UpperHalfPlane.coe_specialLinearGroup_apply] simpa [coe_S, num, denom] using (inv_lt_inv₀ z.normSq_pos zero_lt_one).mpr h
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
normSq_S_smul_lt_one
If `1 < |z|`, then `|S • z| < 1`.
im_lt_im_S_smul (h : normSq z < 1) : z.im < (S • z).im := by rw [ModularGroup.im_smul_eq_div_normSq] have : z.im < z.im / normSq (z : ℂ) := by have imz : 0 < z.im := im_pos z apply (lt_div_iff₀ z.normSq_pos).mpr nlinarith simpa [denom, coe_S, SpecialLinearGroup.toGL]
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
im_lt_im_S_smul
If `|z| < 1`, then applying `S` strictly decreases `im`.
fd : Set ℍ := {z | 1 ≤ normSq (z : ℂ) ∧ |z.re| ≤ (1 : ℝ) / 2}
def
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
fd
The standard (closed) fundamental domain of the action of `SL(2,ℤ)` on `ℍ`.
fdo : Set ℍ := {z | 1 < normSq (z : ℂ) ∧ |z.re| < (1 : ℝ) / 2} @[inherit_doc ModularGroup.fd] scoped[Modular] notation "𝒟" => ModularGroup.fd @[inherit_doc ModularGroup.fdo] scoped[Modular] notation "𝒟ᵒ" => ModularGroup.fdo open scoped Modular
def
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
fdo
The standard open fundamental domain of the action of `SL(2,ℤ)` on `ℍ`.
abs_two_mul_re_lt_one_of_mem_fdo (h : z ∈ 𝒟ᵒ) : |2 * z.re| < 1 := by rw [abs_mul, abs_two, ← lt_div_iff₀' (zero_lt_two' ℝ)] exact h.2
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
abs_two_mul_re_lt_one_of_mem_fdo
null
three_lt_four_mul_im_sq_of_mem_fdo (h : z ∈ 𝒟ᵒ) : 3 < 4 * z.im ^ 2 := by have : 1 < z.re * z.re + z.im * z.im := by simpa [Complex.normSq_apply] using h.1 have := h.2 cases abs_cases z.re <;> nlinarith
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
three_lt_four_mul_im_sq_of_mem_fdo
null
three_le_four_mul_im_sq_of_mem_fd {τ : ℍ} (h : τ ∈ 𝒟) : 3 ≤ 4 * τ.im ^ 2 := by have : 1 ≤ τ.re * τ.re + τ.im * τ.im := by simpa [Complex.normSq_apply] using h.1 cases abs_cases τ.re <;> nlinarith [h.2]
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
three_le_four_mul_im_sq_of_mem_fd
non-strict variant of `ModularGroup.three_le_four_mul_im_sq_of_mem_fdo`
one_lt_normSq_T_zpow_smul (hz : z ∈ 𝒟ᵒ) (n : ℤ) : 1 < normSq (T ^ n • z : ℍ) := by rw [coe_T_zpow_smul_eq] have hz₁ : 1 < z.re * z.re + z.im * z.im := hz.1 have hzn := Int.nneg_mul_add_sq_of_abs_le_one n (abs_two_mul_re_lt_one_of_mem_fdo hz).le have : 1 < (z.re + ↑n) * (z.re + ↑n) + z.im * z.im := by linarith ...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
one_lt_normSq_T_zpow_smul
If `z ∈ 𝒟ᵒ`, and `n : ℤ`, then `|z + n| > 1`.
eq_zero_of_mem_fdo_of_T_zpow_mem_fdo {n : ℤ} (hz : z ∈ 𝒟ᵒ) (hg : T ^ n • z ∈ 𝒟ᵒ) : n = 0 := by suffices |(n : ℝ)| < 1 by rwa [← Int.cast_abs, ← Int.cast_one, Int.cast_lt, Int.abs_lt_one_iff] at this have h₁ := hz.2 have h₂ := hg.2 rw [re_T_zpow_smul] at h₂ calc |(n : ℝ)| ≤ |z.re| + |z.re + (n : ...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
eq_zero_of_mem_fdo_of_T_zpow_mem_fdo
null
exists_smul_mem_fd (z : ℍ) : ∃ g : SL(2, ℤ), g • z ∈ 𝒟 := by obtain ⟨g₀, hg₀⟩ := exists_max_im z obtain ⟨g, hg, hg'⟩ := exists_row_one_eq_and_min_re z (bottom_row_coprime g₀) refine ⟨g, ?_⟩ have hg₀' : ∀ g' : SL(2, ℤ), (g' • z).im ≤ (g • z).im := by have hg'' : (g • z).im = (g₀ • z).im := by rw [Modu...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
exists_smul_mem_fd
First Fundamental Domain Lemma: Any `z : ℍ` can be moved to `𝒟` by an element of `SL(2,ℤ)`
abs_c_le_one (hz : z ∈ 𝒟ᵒ) (hg : g • z ∈ 𝒟ᵒ) : |g 1 0| ≤ 1 := by let c' : ℤ := g 1 0 let c := (c' : ℝ) suffices 3 * c ^ 2 < 4 by rw [← Int.cast_pow, ← Int.cast_three, ← Int.cast_four, ← Int.cast_mul, Int.cast_lt] at this replace this : c' ^ 2 ≤ 1 ^ 2 := by omega rwa [sq_le_sq, abs_one] at this suf...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
abs_c_le_one
An auxiliary result en route to `ModularGroup.c_eq_zero`.
c_eq_zero (hz : z ∈ 𝒟ᵒ) (hg : g • z ∈ 𝒟ᵒ) : g 1 0 = 0 := by have hp : ∀ {g' : SL(2, ℤ)}, g' • z ∈ 𝒟ᵒ → g' 1 0 ≠ 1 := by intro g' hg' by_contra hc let a := g' 0 0 let d := g' 1 1 have had : T ^ (-a) * g' = S * T ^ d := by rw [g_eq_of_c_eq_one hc] dsimp [a, d] group let w :=...
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
c_eq_zero
An auxiliary result en route to `ModularGroup.eq_smul_self_of_mem_fdo_mem_fdo`.
eq_smul_self_of_mem_fdo_mem_fdo (hz : z ∈ 𝒟ᵒ) (hg : g • z ∈ 𝒟ᵒ) : z = g • z := by obtain ⟨n, hn⟩ := exists_eq_T_zpow_of_c_eq_zero (c_eq_zero hz hg) rw [hn] at hg ⊢ simp [eq_zero_of_mem_fdo_of_T_zpow_mem_fdo hz hg, one_smul]
theorem
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
eq_smul_self_of_mem_fdo_mem_fdo
Second Fundamental Domain Lemma: if both `z` and `g • z` are in the open domain `𝒟ᵒ`, where `z : ℍ` and `g : SL(2,ℤ)`, then `z = g • z`.
exists_one_half_le_im_smul (τ : ℍ) : ∃ γ : SL(2, ℤ), 1 / 2 ≤ im (γ • τ) := by obtain ⟨γ, hγ⟩ := exists_smul_mem_fd τ use γ nlinarith [three_le_four_mul_im_sq_of_mem_fd hγ, im_pos (γ • τ)]
lemma
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
exists_one_half_le_im_smul
null
exists_one_half_le_im_smul_and_norm_denom_le (τ : ℍ) : ∃ γ : SL(2, ℤ), 1 / 2 ≤ im (γ • τ) ∧ ‖denom γ τ‖ ≤ 1 := by rcases le_total (1 / 2) τ.im with h | h · exact ⟨1, (one_smul SL(2, ℤ) τ).symm ▸ h, by simp only [map_one, denom_one, norm_one, le_refl]⟩ · refine (exists_one_half_le_im_smul τ).imp (fun γ h...
lemma
NumberTheory
[ "Mathlib.Analysis.Complex.UpperHalfPlane.MoebiusAction", "Mathlib.LinearAlgebra.GeneralLinearGroup", "Mathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic", "Mathlib.Topology.Instances.Matrix", "Mathlib.Topology.Algebra.Module.FiniteDimension", "Mathlib.Topology.Instances.ZMultiples" ]
Mathlib/NumberTheory/Modular.lean
exists_one_half_le_im_smul_and_norm_denom_le
For every `τ : ℍ` there is some `γ ∈ SL(2, ℤ)` that sends it to an element whose imaginary part is at least `1/2` and such that `denom γ τ` has norm at most 1.
dvd_geom_sum₂_iff_of_dvd_sub {x y p : R} (h : p ∣ x - y) : (p ∣ ∑ i ∈ range n, x ^ i * y ^ (n - 1 - i)) ↔ p ∣ n * y ^ (n - 1) := by rw [← mem_span_singleton, ← Ideal.Quotient.eq] at h simp only [← mem_span_singleton, ← eq_zero_iff_mem, RingHom.map_geom_sum₂, h, geom_sum₂_self, map_mul, map_pow, map_natCast]
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
dvd_geom_sum₂_iff_of_dvd_sub
null
dvd_geom_sum₂_iff_of_dvd_sub' {x y p : R} (h : p ∣ x - y) : (p ∣ ∑ i ∈ range n, x ^ i * y ^ (n - 1 - i)) ↔ p ∣ n * x ^ (n - 1) := by rw [geom_sum₂_comm, dvd_geom_sum₂_iff_of_dvd_sub]; simpa using h.neg_right
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
dvd_geom_sum₂_iff_of_dvd_sub'
null
dvd_geom_sum₂_self {x y : R} (h : ↑n ∣ x - y) : ↑n ∣ ∑ i ∈ range n, x ^ i * y ^ (n - 1 - i) := (dvd_geom_sum₂_iff_of_dvd_sub h).mpr (dvd_mul_right _ _)
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
dvd_geom_sum₂_self
null
sq_dvd_add_pow_sub_sub (p x : R) (n : ℕ) : p ^ 2 ∣ (x + p) ^ n - x ^ (n - 1) * p * n - x ^ n := by rcases n with - | n · simp only [pow_zero, Nat.cast_zero, sub_zero, sub_self, dvd_zero, mul_zero] · simp only [Nat.succ_sub_succ_eq_sub, tsub_zero, Nat.cast_succ, add_pow, Finset.sum_range_succ, Nat.choose...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
sq_dvd_add_pow_sub_sub
null
not_dvd_geom_sum₂ {p : R} (hp : Prime p) (hxy : p ∣ x - y) (hx : ¬p ∣ x) (hn : ¬p ∣ n) : ¬p ∣ ∑ i ∈ range n, x ^ i * y ^ (n - 1 - i) := fun h => hx <| hp.dvd_of_dvd_pow <| (hp.dvd_or_dvd <| (dvd_geom_sum₂_iff_of_dvd_sub' hxy).mp h).resolve_left hn variable {p : ℕ} (a b)
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
not_dvd_geom_sum₂
null
odd_sq_dvd_geom_sum₂_sub (hp : Odd p) : (p : R) ^ 2 ∣ (∑ i ∈ range p, (a + p * b) ^ i * a ^ (p - 1 - i)) - p * a ^ (p - 1) := by have h1 : ∀ (i : ℕ), (p : R) ^ 2 ∣ (a + ↑p * b) ^ i - (a ^ (i - 1) * (↑p * b) * i + a ^ i) := by intro i calc ↑p ^ 2 ∣ (↑p * b) ^ 2 := by simp only [mul_pow, dvd_mul...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
odd_sq_dvd_geom_sum₂_sub
null
emultiplicity_pow_sub_pow_of_prime {p : R} (hp : Prime p) {x y : R} (hxy : p ∣ x - y) (hx : ¬p ∣ x) {n : ℕ} (hn : ¬p ∣ n) : emultiplicity p (x ^ n - y ^ n) = emultiplicity p (x - y) := by rw [← geom_sum₂_mul, emultiplicity_mul hp, emultiplicity_eq_zero.2 (not_dvd_geom_sum₂ hp hxy hx hn), zero_add] variabl...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
emultiplicity_pow_sub_pow_of_prime
null
emultiplicity_geom_sum₂_eq_one : emultiplicity (↑p) (∑ i ∈ range p, x ^ i * y ^ (p - 1 - i)) = 1 := by rw [← Nat.cast_one] refine emultiplicity_eq_coe.2 ⟨?_, ?_⟩ · rw [pow_one] exact dvd_geom_sum₂_self hxy rw [dvd_iff_dvd_of_dvd_sub hxy] at hx obtain ⟨k, hk⟩ := hxy rw [one_add_one_eq_two, eq_add_of_...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
emultiplicity_geom_sum₂_eq_one
null
emultiplicity_pow_prime_sub_pow_prime : emultiplicity (↑p) (x ^ p - y ^ p) = emultiplicity (↑p) (x - y) + 1 := by rw [← geom_sum₂_mul, emultiplicity_mul hp, emultiplicity_geom_sum₂_eq_one hp hp1 hxy hx, add_comm]
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
emultiplicity_pow_prime_sub_pow_prime
null
emultiplicity_pow_prime_pow_sub_pow_prime_pow (a : ℕ) : emultiplicity (↑p) (x ^ p ^ a - y ^ p ^ a) = emultiplicity (↑p) (x - y) + a := by induction a with | zero => rw [Nat.cast_zero, add_zero, pow_zero, pow_one, pow_one] | succ a h_ind => rw [Nat.cast_add, Nat.cast_one, ← add_assoc, ← h_ind, pow_succ, po...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
emultiplicity_pow_prime_pow_sub_pow_prime_pow
null
Int.emultiplicity_pow_sub_pow {x y : ℤ} (hxy : ↑p ∣ x - y) (hx : ¬↑p ∣ x) (n : ℕ) : emultiplicity (↑p) (x ^ n - y ^ n) = emultiplicity (↑p) (x - y) + emultiplicity p n := by rcases n with - | n · simp only [emultiplicity_zero, add_top, pow_zero, sub_self] have h : FiniteMultiplicity _ _ := Nat.finiteMultiplic...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.emultiplicity_pow_sub_pow
**Lifting the exponent lemma** for odd primes.
Int.emultiplicity_pow_add_pow {x y : ℤ} (hxy : ↑p ∣ x + y) (hx : ¬↑p ∣ x) {n : ℕ} (hn : Odd n) : emultiplicity (↑p) (x ^ n + y ^ n) = emultiplicity (↑p) (x + y) + emultiplicity p n := by rw [← sub_neg_eq_add] at hxy rw [← sub_neg_eq_add, ← sub_neg_eq_add, ← Odd.neg_pow hn] exact Int.emultiplicity_pow_sub_...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.emultiplicity_pow_add_pow
null
Nat.emultiplicity_pow_sub_pow {x y : ℕ} (hxy : p ∣ x - y) (hx : ¬p ∣ x) (n : ℕ) : emultiplicity p (x ^ n - y ^ n) = emultiplicity p (x - y) + emultiplicity p n := by obtain hyx | hyx := le_total y x · iterate 2 rw [← Int.natCast_emultiplicity] rw [Int.ofNat_sub (Nat.pow_le_pow_left hyx n)] rw [← Int.nat...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Nat.emultiplicity_pow_sub_pow
null
Nat.emultiplicity_pow_add_pow {x y : ℕ} (hxy : p ∣ x + y) (hx : ¬p ∣ x) {n : ℕ} (hn : Odd n) : emultiplicity p (x ^ n + y ^ n) = emultiplicity p (x + y) + emultiplicity p n := by iterate 2 rw [← Int.natCast_emultiplicity] rw [← Int.natCast_dvd_natCast] at hxy hx push_cast at * exact Int.emultiplicity_po...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Nat.emultiplicity_pow_add_pow
null
pow_two_pow_sub_pow_two_pow [CommRing R] {x y : R} (n : ℕ) : x ^ 2 ^ n - y ^ 2 ^ n = (∏ i ∈ Finset.range n, (x ^ 2 ^ i + y ^ 2 ^ i)) * (x - y) := by induction n with | zero => simp only [pow_zero, pow_one, range_zero, prod_empty, one_mul] | succ d hd => suffices x ^ 2 ^ d.succ - y ^ 2 ^ d.succ = (x ^ 2 ^ ...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
pow_two_pow_sub_pow_two_pow
null
Int.sq_mod_four_eq_one_of_odd {x : ℤ} : Odd x → x ^ 2 % 4 = 1 := by intro hx unfold Odd at hx rcases hx with ⟨_, rfl⟩ ring_nf rw [add_assoc, ← add_mul, Int.add_mul_emod_self_right] decide
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.sq_mod_four_eq_one_of_odd
null
Int.eight_dvd_sq_sub_one_of_odd {k : ℤ} (hk : Odd k) : 8 ∣ k ^ 2 - 1 := by rcases hk with ⟨m, rfl⟩ have eq : (2 * m + 1) ^ 2 - 1 = 4 * (m * (m + 1)) := by ring simpa [eq] using (mul_dvd_mul_iff_left four_ne_zero).mpr (two_dvd_mul_add_one m)
lemma
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.eight_dvd_sq_sub_one_of_odd
null
Nat.eight_dvd_sq_sub_one_of_odd {k : ℕ} (hk : Odd k) : 8 ∣ k ^ 2 - 1 := by rcases hk with ⟨m, rfl⟩ have eq : (2 * m + 1) ^ 2 - 1 = 4 * (m * (m + 1)) := by ring_nf; grind simpa [eq] using (mul_dvd_mul_iff_left four_ne_zero).mpr (two_dvd_mul_add_one m)
lemma
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Nat.eight_dvd_sq_sub_one_of_odd
null
Int.two_pow_two_pow_add_two_pow_two_pow {x y : ℤ} (hx : ¬2 ∣ x) (hxy : 4 ∣ x - y) (i : ℕ) : emultiplicity 2 (x ^ 2 ^ i + y ^ 2 ^ i) = ↑(1 : ℕ) := by have hx_odd : Odd x := by rwa [← Int.not_even_iff_odd, even_iff_two_dvd] have hxy_even : Even (x - y) := even_iff_two_dvd.mpr (dvd_trans (by decide) hxy) have hy...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.two_pow_two_pow_add_two_pow_two_pow
null
Int.two_pow_two_pow_sub_pow_two_pow {x y : ℤ} (n : ℕ) (hxy : 4 ∣ x - y) (hx : ¬2 ∣ x) : emultiplicity 2 (x ^ 2 ^ n - y ^ 2 ^ n) = emultiplicity 2 (x - y) + n := by simp only [pow_two_pow_sub_pow_two_pow n, emultiplicity_mul Int.prime_two, Finset.emultiplicity_prod Int.prime_two, add_comm, Nat.cast_one, Finset...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.two_pow_two_pow_sub_pow_two_pow
null
Int.two_pow_sub_pow' {x y : ℤ} (n : ℕ) (hxy : 4 ∣ x - y) (hx : ¬2 ∣ x) : emultiplicity 2 (x ^ n - y ^ n) = emultiplicity 2 (x - y) + emultiplicity (2 : ℤ) n := by have hx_odd : Odd x := by rwa [← Int.not_even_iff_odd, even_iff_two_dvd] have hxy_even : Even (x - y) := even_iff_two_dvd.mpr (dvd_trans (by decide) ...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.two_pow_sub_pow'
null
Int.two_pow_sub_pow {x y : ℤ} {n : ℕ} (hxy : 2 ∣ x - y) (hx : ¬2 ∣ x) (hn : Even n) : emultiplicity 2 (x ^ n - y ^ n) + 1 = emultiplicity 2 (x + y) + emultiplicity 2 (x - y) + emultiplicity (2 : ℤ) n := by have hy : Odd y := by rw [← even_iff_two_dvd, Int.not_even_iff_odd] at hx replace hxy := (@eve...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Int.two_pow_sub_pow
**Lifting the exponent lemma** for `p = 2`
Nat.two_pow_sub_pow {x y : ℕ} (hxy : 2 ∣ x - y) (hx : ¬2 ∣ x) {n : ℕ} (hn : Even n) : emultiplicity 2 (x ^ n - y ^ n) + 1 = emultiplicity 2 (x + y) + emultiplicity 2 (x - y) + emultiplicity 2 n := by obtain hyx | hyx := le_total y x · iterate 3 rw [← Int.natCast_emultiplicity] simp only [Int.ofNat_sub...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
Nat.two_pow_sub_pow
null
pow_two_sub_pow (hyx : y < x) (hxy : 2 ∣ x - y) (hx : ¬2 ∣ x) {n : ℕ} (hn : n ≠ 0) (hneven : Even n) : padicValNat 2 (x ^ n - y ^ n) + 1 = padicValNat 2 (x + y) + padicValNat 2 (x - y) + padicValNat 2 n := by simp only [← Nat.cast_inj (R := ℕ∞), Nat.cast_add] iterate 4 rw [padicValNat_eq_emultiplicity...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
pow_two_sub_pow
null
pow_sub_pow (hyx : y < x) (hxy : p ∣ x - y) (hx : ¬p ∣ x) {n : ℕ} (hn : n ≠ 0) : padicValNat p (x ^ n - y ^ n) = padicValNat p (x - y) + padicValNat p n := by rw [← Nat.cast_inj (R := ℕ∞), Nat.cast_add] iterate 3 rw [padicValNat_eq_emultiplicity] · exact Nat.emultiplicity_pow_sub_pow hp.out hp1 hxy hx n · e...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
pow_sub_pow
null
pow_add_pow (hxy : p ∣ x + y) (hx : ¬p ∣ x) {n : ℕ} (hn : Odd n) : padicValNat p (x ^ n + y ^ n) = padicValNat p (x + y) + padicValNat p n := by rcases y with - | y · contradiction rw [← Nat.cast_inj (R := ℕ∞), Nat.cast_add] iterate 3 rw [padicValNat_eq_emultiplicity] · exact Nat.emultiplicity_pow_add_pow...
theorem
NumberTheory
[ "Mathlib.Algebra.Order.Ring.Basic", "Mathlib.Algebra.Ring.GeomSum", "Mathlib.Algebra.Ring.Int.Parity", "Mathlib.Data.Nat.Choose.Sum", "Mathlib.Data.Nat.Prime.Int", "Mathlib.NumberTheory.Padics.PadicVal.Defs", "Mathlib.RingTheory.Ideal.Quotient.Defs", "Mathlib.RingTheory.Ideal.Span" ]
Mathlib/NumberTheory/Multiplicity.lean
pow_add_pow
null
@[simp] ratCast_iff : IsIntegral ℤ (q : α) ↔ IsIntegral ℤ q := isIntegral_algebraMap_iff (FaithfulSMul.algebraMap_injective ℚ α)
theorem
NumberTheory
[ "Mathlib.Analysis.SpecialFunctions.Complex.Log", "Mathlib.RingTheory.Polynomial.RationalRoot", "Mathlib.Tactic.Peel", "Mathlib.Tactic.Rify" ]
Mathlib/NumberTheory/Niven.lean
ratCast_iff
null
exists_int_iff_exists_rat (h₁ : IsIntegral ℤ x) : (∃ q : ℚ, x = q) ↔ ∃ k : ℤ, x = k := by refine ⟨?_, fun ⟨w, h⟩ ↦ ⟨w, by simp [h]⟩⟩ rintro ⟨q, rfl⟩ rw [ratCast_iff] at h₁ peel IsIntegrallyClosed.algebraMap_eq_of_integral h₁ with h simp [← h]
theorem
NumberTheory
[ "Mathlib.Analysis.SpecialFunctions.Complex.Log", "Mathlib.RingTheory.Polynomial.RationalRoot", "Mathlib.Tactic.Peel", "Mathlib.Tactic.Rify" ]
Mathlib/NumberTheory/Niven.lean
exists_int_iff_exists_rat
null
isIntegral_two_mul_cos_rat_mul_pi (r : ℚ) : IsIntegral ℤ (2 * cos (r * π)) := by let z : ℂ := .exp (.I * r * π) obtain ⟨p, q, hq_pos, rfl⟩ : ∃ (p : ℤ) (q : ℕ), q ≠ 0 ∧ r = p / q := ⟨r.num, r.den, r.den_ne_zero, r.num_div_den.symm⟩ have hz_root : z ^ (2 * q) = 1 := by rw [← Complex.exp_nat_mul, Complex...
theorem
NumberTheory
[ "Mathlib.Analysis.SpecialFunctions.Complex.Log", "Mathlib.RingTheory.Polynomial.RationalRoot", "Mathlib.Tactic.Peel", "Mathlib.Tactic.Rify" ]
Mathlib/NumberTheory/Niven.lean
isIntegral_two_mul_cos_rat_mul_pi
null
niven (hθ : ∃ r : ℚ, θ = r * π) (hcos : ∃ q : ℚ, cos θ = q) : cos θ ∈ ({-1, -1 / 2, 0, 1 / 2, 1} : Set ℝ) := by obtain ⟨r, rfl⟩ := hθ obtain ⟨k, hk⟩ : ∃ k : ℤ, 2 * cos (r * π) = k := by rw [← (isIntegral_two_mul_cos_rat_mul_pi r).exists_int_iff_exists_rat] exact ⟨2 * hcos.choose, by push_cast; linarith ...
theorem
NumberTheory
[ "Mathlib.Analysis.SpecialFunctions.Complex.Log", "Mathlib.RingTheory.Polynomial.RationalRoot", "Mathlib.Tactic.Peel", "Mathlib.Tactic.Rify" ]
Mathlib/NumberTheory/Niven.lean
niven
**Niven's theorem**: The only rational values of `cos` that occur at rational multiples of π are `{-1, -1/2, 0, 1/2, 1}`.
niven_sin (hθ : ∃ r : ℚ, θ = r * π) (hcos : ∃ q : ℚ, sin θ = q) : sin θ ∈ ({-1, -1 / 2, 0, 1 / 2, 1} : Set ℝ) := by convert ← niven (θ := θ - π/2) ?_ ?_ using 1 · exact cos_sub_pi_div_two θ · exact hθ.imp' (· - 1 / 2) (by intros; push_cast; linarith) · simpa [cos_sub_pi_div_two]
theorem
NumberTheory
[ "Mathlib.Analysis.SpecialFunctions.Complex.Log", "Mathlib.RingTheory.Polynomial.RationalRoot", "Mathlib.Tactic.Peel", "Mathlib.Tactic.Rify" ]
Mathlib/NumberTheory/Niven.lean
niven_sin
Niven's theorem, but stated for `sin` instead of `cos`.
niven_angle_eq (hθ : ∃ r : ℚ, θ = r * π) (hcos : ∃ q : ℚ, cos θ = q) (h_bnd : θ ∈ Set.Icc 0 π) : θ ∈ ({0, π / 3, π / 2, π * (2 / 3), π} : Set ℝ) := by rcases niven hθ hcos with h | h | h | h | h <;> [ have h₂ := cos_pi; have h₂ : cos (π * (2 / 3)) = -1 / 2 := by have := cos_pi_sub (π / 3) have :...
theorem
NumberTheory
[ "Mathlib.Analysis.SpecialFunctions.Complex.Log", "Mathlib.RingTheory.Polynomial.RationalRoot", "Mathlib.Tactic.Peel", "Mathlib.Tactic.Rify" ]
Mathlib/NumberTheory/Niven.lean
niven_angle_eq
Niven's theorem, giving the possible angles for `θ` in the range `0 .. π`.