Metamath Proof Explorer


Theorem relresOLD

Description: Obsolete version of relres as of 16-Oct-2026. (Contributed by NM, 2-Aug-1994) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion relresOLD
|- Rel ( A |` B )

Proof

Step Hyp Ref Expression
1 df-res
 |-  ( A |` B ) = ( A i^i ( B X. _V ) )
2 inss2
 |-  ( A i^i ( B X. _V ) ) C_ ( B X. _V )
3 1 2 eqsstri
 |-  ( A |` B ) C_ ( B X. _V )
4 relxp
 |-  Rel ( B X. _V )
5 relss
 |-  ( ( A |` B ) C_ ( B X. _V ) -> ( Rel ( B X. _V ) -> Rel ( A |` B ) ) )
6 3 4 5 mp2
 |-  Rel ( A |` B )