2014-08-24 19:58:48 -07:00
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import logic
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2014-09-03 16:00:38 -07:00
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open tactic
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2014-06-30 00:51:11 -07:00
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2014-07-22 09:43:18 -07:00
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theorem tst (a b : Prop) (H : a ↔ b) : b ↔ a
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2014-09-08 07:47:42 -07:00
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:= have H1 [visible] : a → b, -- We need to mark H1 as fact, otherwise it is not visible by tactics
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2014-09-04 21:25:21 -07:00
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from iff.elim_left H,
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by apply iff.intro;
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apply (assume Hb, iff.elim_right H Hb);
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2014-07-04 10:10:05 -07:00
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apply (assume Ha, H1 Ha)
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