Metamath Proof Explorer


Theorem wlkelwrd

Description: The components of a walk are words/functions over a zero based range of integers. (Contributed by Alexander van der Vekens, 23-Jun-2018) (Revised by AV, 2-Jan-2021)

Ref Expression
Hypotheses wlkcomp.v
|- V = ( Vtx ` G )
wlkcomp.i
|- I = ( iEdg ` G )
wlkcomp.1
|- F = ( 1st ` W )
wlkcomp.2
|- P = ( 2nd ` W )
Assertion wlkelwrd
|- ( W e. ( Walks ` G ) -> ( F e. Word dom I /\ P : ( 0 ... ( # ` F ) ) --> V ) )

Proof

Step Hyp Ref Expression
1 wlkcomp.v
 |-  V = ( Vtx ` G )
2 wlkcomp.i
 |-  I = ( iEdg ` G )
3 wlkcomp.1
 |-  F = ( 1st ` W )
4 wlkcomp.2
 |-  P = ( 2nd ` W )
5 1 2 3 4 wlkcompim
 |-  ( W e. ( Walks ` G ) -> ( F e. Word dom I /\ P : ( 0 ... ( # ` F ) ) --> V /\ A. k e. ( 0 ..^ ( # ` F ) ) if- ( ( P ` k ) = ( P ` ( k + 1 ) ) , ( I ` ( F ` k ) ) = { ( P ` k ) } , { ( P ` k ) , ( P ` ( k + 1 ) ) } C_ ( I ` ( F ` k ) ) ) ) )
6 3simpa
 |-  ( ( F e. Word dom I /\ P : ( 0 ... ( # ` F ) ) --> V /\ A. k e. ( 0 ..^ ( # ` F ) ) if- ( ( P ` k ) = ( P ` ( k + 1 ) ) , ( I ` ( F ` k ) ) = { ( P ` k ) } , { ( P ` k ) , ( P ` ( k + 1 ) ) } C_ ( I ` ( F ` k ) ) ) ) -> ( F e. Word dom I /\ P : ( 0 ... ( # ` F ) ) --> V ) )
7 5 6 syl
 |-  ( W e. ( Walks ` G ) -> ( F e. Word dom I /\ P : ( 0 ... ( # ` F ) ) --> V ) )