Description: A weak version of ax-12 which is stronger than ax12v . Note that if one assumes reflexivity of equality |- x = x ( equid ), then bj-ax12v3 implies ax-5 over modal logic K (substitute x for y ). See also bj-ax12v3ALT . (Contributed by BJ, 6-Jul-2021) (Proof modification is discouraged.)
Ref | Expression | ||
---|---|---|---|
Assertion | bj-ax12v3 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ax-5 | |
|
2 | ax12 | |
|
3 | 1 2 | syl5 | |