11 lines
294 B
Text
11 lines
294 B
Text
import logic
|
||
open tactic
|
||
|
||
theorem tst (a b : Prop) (H : ¬ a ∨ ¬ b) (Hb : b) : ¬ a ∧ b
|
||
:= by apply and.intro;
|
||
apply not_intro;
|
||
exact
|
||
(assume Ha, or.elim H
|
||
(assume Hna, @absurd _ false Ha Hna)
|
||
(assume Hnb, @absurd _ false Hb Hnb));
|
||
assumption
|