Metamath Proof Explorer


Theorem nfwe

Description: Bound-variable hypothesis builder for well-orderings. (Contributed by Stefan O'Rear, 20-Jan-2015) (Revised by Mario Carneiro, 14-Oct-2016)

Ref Expression
Hypotheses nffr.r _ x R
nffr.a _ x A
Assertion nfwe x R We A

Proof

Step Hyp Ref Expression
1 nffr.r _ x R
2 nffr.a _ x A
3 df-we R We A R Fr A R Or A
4 1 2 nffr x R Fr A
5 1 2 nfso x R Or A
6 4 5 nfan x R Fr A R Or A
7 3 6 nfxfr x R We A