12 lines
No EOL
248 B
Text
12 lines
No EOL
248 B
Text
import standard
|
||
using tactic
|
||
|
||
theorem tst (a b : Bool) (H : ¬ a ∨ ¬ b) (Hb : b) : ¬ a ∧ b :=
|
||
proof
|
||
apply and_intro,
|
||
apply not_intro,
|
||
assume Ha, or_elim H
|
||
(assume Hna, absurd Ha Hna)
|
||
(assume Hnb, absurd Hb Hnb),
|
||
assumption
|
||
qed |