Metamath Proof Explorer


Theorem ensymd

Description: Symmetry of equinumerosity. Deduction form of ensym . (Contributed by David Moews, 1-May-2017)

Ref Expression
Hypothesis ensymd.1 φAB
Assertion ensymd φBA

Proof

Step Hyp Ref Expression
1 ensymd.1 φAB
2 ensym ABBA
3 1 2 syl φBA