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Author SHA1 Message Date
Scott Morrison
8bf8acdeb9 chore: correct statement of Int.pow_zero, and protected theorems 2024-03-01 23:23:03 +11:00
4 changed files with 8 additions and 8 deletions

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@@ -501,7 +501,7 @@ theorem eq_one_of_mul_eq_self_right {a b : Int} (Hpos : b ≠ 0) (H : b * a = b)
/-! # pow -/
theorem pow_zero (n : Nat) : n^0 = 1 := rfl
protected theorem pow_zero (b : Int) : b^0 = 1 := rfl
protected theorem pow_succ (b : Int) (e : Nat) : b ^ (e+1) = (b ^ e) * b := rfl
protected theorem pow_succ' (b : Int) (e : Nat) : b ^ (e+1) = b * (b ^ e) := by

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@@ -503,10 +503,10 @@ theorem eq_of_mul_eq_mul_right {n m k : Nat} (hm : 0 < m) (h : n * m = k * m) :
/-! # power -/
theorem pow_succ (n m : Nat) : n^(succ m) = n^m * n :=
protected theorem pow_succ (n m : Nat) : n^(succ m) = n^m * n :=
rfl
theorem pow_zero (n : Nat) : n^0 = 1 := rfl
protected theorem pow_zero (n : Nat) : n^0 = 1 := rfl
theorem pow_le_pow_of_le_left {n m : Nat} (h : n m) : (i : Nat), n^i m^i
| 0 => Nat.le_refl _

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@@ -239,7 +239,7 @@ theorem testBit_two_pow_add_gt {i j : Nat} (j_lt_i : j < i) (x : Nat) :
rw [Nat.sub_eq_zero_iff_le] at i_sub_j_eq
exact Nat.not_le_of_gt j_lt_i i_sub_j_eq
| d+1 =>
simp [pow_succ, Nat.mul_comm _ 2, Nat.mul_add_mod]
simp [Nat.pow_succ, Nat.mul_comm _ 2, Nat.mul_add_mod]
@[simp] theorem testBit_mod_two_pow (x j i : Nat) :
testBit (x % 2^j) i = (decide (i < j) && testBit x i) := by
@@ -287,7 +287,7 @@ theorem testBit_two_pow_sub_succ (h₂ : x < 2 ^ n) (i : Nat) :
simp only [testBit_succ]
match n with
| 0 =>
simp only [pow_zero, succ_sub_succ_eq_sub, Nat.zero_sub, Nat.zero_div, zero_testBit]
simp only [Nat.pow_zero, succ_sub_succ_eq_sub, Nat.zero_sub, Nat.zero_div, zero_testBit]
rw [decide_eq_false] <;> simp
| n+1 =>
rw [Nat.two_pow_succ_sub_succ_div_two, ih]
@@ -352,7 +352,7 @@ private theorem eq_0_of_lt (x : Nat) : x < 2^ 0 ↔ x = 0 := eq_0_of_lt_one x
private theorem zero_lt_pow (n : Nat) : 0 < 2^n := by
induction n
case zero => simp [eq_0_of_lt]
case succ n hyp => simpa [pow_succ]
case succ n hyp => simpa [Nat.pow_succ]
private theorem div_two_le_of_lt_two {m n : Nat} (p : m < 2 ^ succ n) : m / 2 < 2^n := by
simp [div_lt_iff_lt_mul Nat.zero_lt_two]
@@ -377,7 +377,7 @@ theorem bitwise_lt_two_pow (left : x < 2^n) (right : y < 2^n) : (Nat.bitwise f x
simp only [x_zero, y_zero, if_neg]
have hyp1 := hyp (div_two_le_of_lt_two left) (div_two_le_of_lt_two right)
by_cases p : f (decide (x % 2 = 1)) (decide (y % 2 = 1)) = true <;>
simp [p, pow_succ, mul_succ, Nat.add_assoc]
simp [p, Nat.pow_succ, mul_succ, Nat.add_assoc]
case pos =>
apply lt_of_succ_le
simp only [ Nat.succ_add]

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@@ -742,7 +742,7 @@ theorem shiftLeft_eq (a b : Nat) : a <<< b = a * 2 ^ b :=
match b with
| 0 => (Nat.mul_one _).symm
| b+1 => (shiftLeft_eq _ b).trans <| by
simp [pow_succ, Nat.mul_assoc, Nat.mul_left_comm, Nat.mul_comm]
simp [Nat.pow_succ, Nat.mul_assoc, Nat.mul_left_comm, Nat.mul_comm]
theorem one_shiftLeft (n : Nat) : 1 <<< n = 2 ^ n := by rw [shiftLeft_eq, Nat.one_mul]