16 lines
285 B
Text
16 lines
285 B
Text
import standard
|
||
using 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 Ha Hna)
|
||
(assume Hnb, absurd Hb Hnb));
|
||
assumption
|
||
|
||
|
||
|
||
|
||
|