Metamath Proof Explorer


Theorem relres

Description: A restriction is a relation. Exercise 12 of TakeutiZaring p. 25. (Contributed by NM, 2-Aug-1994) (Proof shortened by Andrew Salmon, 27-Aug-2011) (Proof shortened by BJ, 16-Oct-2026)

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

Proof

Step Hyp Ref Expression
1 relinxp
 |-  Rel ( A i^i ( B X. _V ) )
2 df-res
 |-  ( A |` B ) = ( A i^i ( B X. _V ) )
3 2 releqi
 |-  ( Rel ( A |` B ) <-> Rel ( A i^i ( B X. _V ) ) )
4 1 3 mpbir
 |-  Rel ( A |` B )