44 lines
1.5 KiB
Text
44 lines
1.5 KiB
Text
/-
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Copyright (c) 2015 Jeremy Avigad. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Jeremy Avigad
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The power function on the integers.
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-/
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import data.int.basic data.int.order data.int.div algebra.group_power data.nat.power
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namespace int
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section migrate_algebra
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open [classes] algebra
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local attribute int.integral_domain [instance]
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local attribute int.linear_ordered_comm_ring [instance]
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local attribute int.decidable_linear_ordered_comm_ring [instance]
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definition pow (a : ℤ) (n : ℕ) : ℤ := algebra.pow a n
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infix [priority int.prio] ^ := pow
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definition nmul (n : ℕ) (a : ℤ) : ℤ := algebra.nmul n a
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infix [priority int.prio] `⬝` := nmul
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definition imul (i : ℤ) (a : ℤ) : ℤ := algebra.imul i a
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migrate from algebra with int
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replacing dvd → dvd, sub → sub, has_le.ge → ge, has_lt.gt → gt, min → min, max → max,
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abs → abs, sign → sign, pow → pow, nmul → nmul, imul → imul
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hiding add_pos_of_pos_of_nonneg, add_pos_of_nonneg_of_pos,
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add_eq_zero_iff_eq_zero_and_eq_zero_of_nonneg_of_nonneg, le_add_of_nonneg_of_le,
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le_add_of_le_of_nonneg, lt_add_of_nonneg_of_lt, lt_add_of_lt_of_nonneg,
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lt_of_mul_lt_mul_left, lt_of_mul_lt_mul_right, pos_of_mul_pos_left, pos_of_mul_pos_right
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end migrate_algebra
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section
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open nat
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theorem of_nat_pow (a n : ℕ) : of_nat (a^n) = (of_nat a)^n :=
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begin
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induction n with n ih,
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apply eq.refl,
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rewrite [pow_succ, nat.pow_succ, of_nat_mul, ih]
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end
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end
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end int
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