12 lines
263 B
Text
12 lines
263 B
Text
import logic
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open tactic
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theorem tst (a b : Prop) (H : ¬ a ∨ ¬ b) (Hb : b) : ¬ a ∧ b :=
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begin
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apply and.intro,
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apply not_intro,
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assume Ha, or.elim H
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(assume Hna, @absurd _ false Ha Hna)
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(assume Hnb, @absurd _ false Hb Hnb),
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assumption
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end
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