lean2/tests/lean/tactic9.lean

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Definition f(a : Bool) : Bool := not a.
Theorem T (a b : Bool) : a \/ b => (f b) => a := _.
apply imp_tac
apply imp_tac
apply disj_hyp_tac
apply (** unfold_tac("f") **)
apply assumption_tac
apply absurd_tac
done
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