13 lines
237 B
Text
13 lines
237 B
Text
exit
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import logic
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open tactic
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constant A : Type.{1}
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constant f : A → A → A
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theorem tst {a b c : A} (H1 : a = b) (H2 : b = c) : f a b = f b c :=
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begin
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apply (@congr A A (f a) (f b)),
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apply (congr_arg f),
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repeat assumption
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end
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