let G be WGraph; for x, y, e being set st e Joins x,y,G holds
(G .walkOf x,e,y) .weightSeq() = <*((the_Weight_of G) . e)*>
let x, y, e be set ; ( e Joins x,y,G implies (G .walkOf x,e,y) .weightSeq() = <*((the_Weight_of G) . e)*> )
set W = G .walkOf x,e,y;
assume
e Joins x,y,G
; (G .walkOf x,e,y) .weightSeq() = <*((the_Weight_of G) . e)*>
then A1:
(G .walkOf x,e,y) .edgeSeq() = <*e*>
by GLIB_001:84;
then
len ((G .walkOf x,e,y) .edgeSeq() ) = 1
by FINSEQ_1:56;
then A2:
len ((G .walkOf x,e,y) .weightSeq() ) = 1
by Def18;
A3:
now let n be
Nat;
( 1 <= n & n <= len ((G .walkOf x,e,y) .weightSeq() ) implies ((G .walkOf x,e,y) .weightSeq() ) . n = <*((the_Weight_of G) . e)*> . n )assume that A4:
1
<= n
and A5:
n <= len ((G .walkOf x,e,y) .weightSeq() )
;
((G .walkOf x,e,y) .weightSeq() ) . n = <*((the_Weight_of G) . e)*> . nA6:
n = 1
by A2, A4, A5, XXREAL_0:1;
hence ((G .walkOf x,e,y) .weightSeq() ) . n =
(the_Weight_of G) . (<*e*> . 1)
by A1, A5, Def18
.=
(the_Weight_of G) . e
by FINSEQ_1:57
.=
<*((the_Weight_of G) . e)*> . n
by A6, FINSEQ_1:57
;
verum end;
len ((G .walkOf x,e,y) .weightSeq() ) = len <*((the_Weight_of G) . e)*>
by A2, FINSEQ_1:56;
hence
(G .walkOf x,e,y) .weightSeq() = <*((the_Weight_of G) . e)*>
by A3, FINSEQ_1:18; verum