Documentation

Mathlib.Data.Int.SuccPred

Successors and predecessors of integers #

In this file, we show that ℤ is both an archimedean SuccOrder and an archimedean PredOrder.

@[reducible]
Equations
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@[reducible]
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@[simp]
theorem Int.succ_eq_succ :
Order.succ = Int.succ
@[simp]
theorem Int.pred_eq_pred :
Order.pred = Int.pred
theorem Int.pos_iff_one_le {a : ℤ} :
0 < a ↔ 1 ≤ a
theorem Int.succ_iterate (a : ℤ) (n : ℕ) :
Int.succ^[n] a = a + ↑n
theorem Int.pred_iterate (a : ℤ) (n : ℕ) :
Int.pred^[n] a = a - ↑n

Covering relation #

theorem Int.covBy_iff_succ_eq {m : ℤ} {n : ℤ} :
m ⋖ n ↔ m + 1 = n
@[simp]
theorem Int.sub_one_covBy (z : ℤ) :
z - 1 ⋖ z
@[simp]
theorem Int.covBy_add_one (z : ℤ) :
z ⋖ z + 1
@[simp]
theorem Nat.cast_int_covBy_iff {a : ℕ} {b : ℕ} :
↑a ⋖ ↑b ↔ a ⋖ b
theorem CovBy.cast_int {a : ℕ} {b : ℕ} :
a ⋖ b → ↑a ⋖ ↑b

Alias of the reverse direction of Nat.cast_int_covBy_iff.