11 lines
222 B
Text
11 lines
222 B
Text
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Variables a b c d e : Nat.
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Variable f : Nat -> Nat.
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Axiom H1 : f a = a.
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Theorem T : f (f (f a)) = a
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:= calc f (f (f a)) = f (f a) : { H1 }
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... = f a : { H1 }
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... = a : { H1 }.
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