lean2/tests/lean/run/tactic11.lean
Leonardo de Moura 5eaf04518b refactor(*): rename Bool to Prop
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2014-07-22 09:43:18 -07:00

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Text

import standard
using tactic
theorem tst (a b : Prop) (H : a ↔ b) : b ↔ a
:= have H1 [fact] : a → b, -- We need to mark H1 as fact, otherwise it is not visible by tactics
from iff_elim_left H,
by apply iff_intro;
apply (assume Hb, iff_mp_right H Hb);
apply (assume Ha, H1 Ha)