Description: Symmetry of equinumerosity. Deduction form of ensym . (Contributed by David Moews, 1-May-2017)
Ref | Expression | ||
---|---|---|---|
Hypothesis | ensymd.1 | |- ( ph -> A ~~ B ) |
|
Assertion | ensymd | |- ( ph -> B ~~ A ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ensymd.1 | |- ( ph -> A ~~ B ) |
|
2 | ensym | |- ( A ~~ B -> B ~~ A ) |
|
3 | 1 2 | syl | |- ( ph -> B ~~ A ) |