Description: A special case of sbequ1 . (Contributed by BJ, 22-Dec-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | bj-ssbid1 | |- ( ph -> [ x / x ] ph ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | equid | |- x = x |
|
2 | sbequ1 | |- ( x = x -> ( ph -> [ x / x ] ph ) ) |
|
3 | 1 2 | ax-mp | |- ( ph -> [ x / x ] ph ) |