let G be _Graph; for W being Walk of G
for n being odd Element of NAT st n <= len W holds
W .cut (n,n) = <*(W .vertexAt n)*>
let W be Walk of G; for n being odd Element of NAT st n <= len W holds
W .cut (n,n) = <*(W .vertexAt n)*>
let n be odd Element of NAT ; ( n <= len W implies W .cut (n,n) = <*(W .vertexAt n)*> )
A1:
1 <= n
by ABIAN:12;
assume A2:
n <= len W
; W .cut (n,n) = <*(W .vertexAt n)*>
then A3:
W . n = W .vertexAt n
by Def8;
W .cut (n,n) = (n,n) -cut W
by A2, Def11;
hence
W .cut (n,n) = <*(W .vertexAt n)*>
by A2, A3, A1, FINSEQ_6:132; verum