6 lines
295 B
Text
6 lines
295 B
Text
example (a b c : nat) (f : nat → nat → nat) (H₁ : a = b) (H₂ : b = c) : f (f a a) (f b b) = f (f c c) (f c c) :=
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have h : a = c, from eq.trans H₁ H₂,
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proof
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calc f (f a a) (f b b) = f (f c c) (f b b) : by rewrite h
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... = f (f c c) (f c c) : by rewrite H₂
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qed
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