Metamath Proof Explorer


Theorem weeq12d

Description: Equality deduction for well-orders. (Contributed by Stefan O'Rear, 19-Jan-2015)

Ref Expression
Hypotheses weeq12d.l φ R = S
weeq12d.r φ A = B
Assertion weeq12d φ R We A S We B

Proof

Step Hyp Ref Expression
1 weeq12d.l φ R = S
2 weeq12d.r φ A = B
3 weeq1 R = S R We A S We A
4 1 3 syl φ R We A S We A
5 weeq2 A = B S We A S We B
6 2 5 syl φ S We A S We B
7 4 6 bitrd φ R We A S We B