17 lines
285 B
Text
17 lines
285 B
Text
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import standard
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using tactic
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theorem tst (a b : Bool) (H : ¬ a ∨ ¬ b) (Hb : b) : ¬ a ∧ b
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:= by apply and_intro;
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apply not_intro;
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exact
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(assume Ha, or_elim H
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(assume Hna, absurd Ha Hna)
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(assume Hnb, absurd Hb Hnb));
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assumption
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