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 φ A B
Assertion ensymd φ B A

Proof

Step Hyp Ref Expression
1 ensymd.1 φ A B
2 ensym A B B A
3 1 2 syl φ B A