Metamath Proof Explorer


Theorem nfbr

Description: Bound-variable hypothesis builder for binary relation. (Contributed by NM, 1-Sep-1999) (Revised by Mario Carneiro, 14-Oct-2016)

Ref Expression
Hypotheses nfbr.1
|- F/_ x A
nfbr.2
|- F/_ x R
nfbr.3
|- F/_ x B
Assertion nfbr
|- F/ x A R B

Proof

Step Hyp Ref Expression
1 nfbr.1
 |-  F/_ x A
2 nfbr.2
 |-  F/_ x R
3 nfbr.3
 |-  F/_ x B
4 1 a1i
 |-  ( T. -> F/_ x A )
5 2 a1i
 |-  ( T. -> F/_ x R )
6 3 a1i
 |-  ( T. -> F/_ x B )
7 4 5 6 nfbrd
 |-  ( T. -> F/ x A R B )
8 7 mptru
 |-  F/ x A R B