Metamath Proof Explorer


Theorem wlkRes

Description: Restrictions of walks (i.e. special kinds of walks, for example paths - see pthsfval ) are sets. (Contributed by Alexander van der Vekens, 1-Nov-2017) (Revised by AV, 30-Dec-2020) (Proof shortened by AV, 15-Jan-2021)

Ref Expression
Hypothesis wlkRes.1
|- ( f ( W ` G ) p -> f ( Walks ` G ) p )
Assertion wlkRes
|- { <. f , p >. | ( f ( W ` G ) p /\ ph ) } e. _V

Proof

Step Hyp Ref Expression
1 wlkRes.1
 |-  ( f ( W ` G ) p -> f ( Walks ` G ) p )
2 1 gen2
 |-  A. f A. p ( f ( W ` G ) p -> f ( Walks ` G ) p )
3 wksv
 |-  { <. f , p >. | f ( Walks ` G ) p } e. _V
4 opabbrex
 |-  ( ( A. f A. p ( f ( W ` G ) p -> f ( Walks ` G ) p ) /\ { <. f , p >. | f ( Walks ` G ) p } e. _V ) -> { <. f , p >. | ( f ( W ` G ) p /\ ph ) } e. _V )
5 2 3 4 mp2an
 |-  { <. f , p >. | ( f ( W ` G ) p /\ ph ) } e. _V