let G be _Graph; for e, x being set st e Joins x,x,G holds
G .walkOf x,e,x is Cycle-like
let e, x be set ; ( e Joins x,x,G implies G .walkOf x,e,x is Cycle-like )
set W = G .walkOf x,e,x;
assume
e Joins x,x,G
; G .walkOf x,e,x is Cycle-like
then
len (G .walkOf x,e,x) = 3
by Th15;
then
not G .walkOf x,e,x is trivial
by Lm54;
hence
G .walkOf x,e,x is Cycle-like
by Def31; verum