23 lines
388 B
Text
23 lines
388 B
Text
import algebra.group
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open algebra
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section
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variable {A : Type}
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variable [s : comm_monoid A]
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include s
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theorem one_mul_one : 1 * 1 = (1:A) :=
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mul_one 1
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end
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definition one [reducible] (A : Type) [s : has_one A] : A :=
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!has_one.one
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section
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variable {A : Type}
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variable [s : comm_group A]
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include s
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theorem one_mul_one2 : (one A) * 1 = 1 :=
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by rewrite one_mul_one
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end
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