lean2/tests/lean/run/tactic13.lean

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