2014-08-25 02:58:48 +00:00
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import logic
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2014-06-30 07:51:11 +00:00
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2014-07-22 16:43:18 +00:00
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theorem tst (a b : Prop) (H : a ↔ b) : b ↔ a
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2014-10-23 01:11:09 +00:00
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:= by rapply iff.intro;
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2014-10-24 05:36:32 +00:00
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intro Ha;
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apply (iff.elim_left H Ha);
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intro Hb;
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apply (iff.elim_right H Hb)
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2014-07-02 20:14:50 +00:00
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check tst
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