[Merged by Bors] - feat(algebra/group_power/lemmas): sign of even/odd powers #5990
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benjamindavidson
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src/algebra/group_power/lemmas.lean
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| theorem even_pow_nonneg (a : R) (hn : even n) : 0 ≤ a ^ n := | ||
| by cases hn with k hk; simpa only [hk, two_mul] using pow_bit0_nonneg a k | ||
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| theorem even_pow_pos (ha : a ≠ 0) (hn : even n) : 0 < a ^ n := | ||
| by cases hn with k hk; simpa only [hk, two_mul] using pow_bit0_pos ha k |
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Shouldn't these be called pow_even_nonneg? Using pow_bit0_nonneg as a template, statements about the exponent go after the word pow not before.
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Indeed, you're right, I should have looked more closely at the naming.
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@eric-wieser @robertylewis Fixed!
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Added theorems about the sign of even and odd natural powers.
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Added theorems about the sign of even and odd natural powers.
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Added theorems about the sign of even and odd natural powers.