let G be _Graph; :: thesis: for S being non empty Subset of (the_Vertices_of G)
for H being inducedSubgraph of G,S
for W being Walk of H st W is minlength holds
for m, n being natural odd number st m + 2 < n & n <= len W holds
for e being set holds not e Joins W . m,W . n,G
let S be non empty Subset of (the_Vertices_of G); :: thesis: for H being inducedSubgraph of G,S
for W being Walk of H st W is minlength holds
for m, n being natural odd number st m + 2 < n & n <= len W holds
for e being set holds not e Joins W . m,W . n,G
let GA be inducedSubgraph of G,S; :: thesis: for W being Walk of GA st W is minlength holds
for m, n being natural odd number st m + 2 < n & n <= len W holds
for e being set holds not e Joins W . m,W . n,G
let P be Walk of GA; :: thesis: ( P is minlength implies for m, n being natural odd number st m + 2 < n & n <= len P holds
for e being set holds not e Joins P . m,P . n,G )
assume A1:
P is minlength
; :: thesis: for m, n being natural odd number st m + 2 < n & n <= len P holds
for e being set holds not e Joins P . m,P . n,G
A2:
S = the_Vertices_of GA
by GLIB_000:def 39;
now let m,
n be
odd Nat;
:: thesis: ( m + 2 < n & n <= len P implies for e being set holds not e Joins P . m,P . n,G )assume A3:
(
m + 2
< n &
n <= len P )
;
:: thesis: for e being set holds not e Joins P . m,P . n,GA4:
(
m in NAT &
n in NAT )
by ORDINAL1:def 13;
let e be
set ;
:: thesis: not e Joins P . m,P . n,Gassume A5:
e Joins P . m,
P . n,
G
;
:: thesis: contradiction
m + 0 <= m + 2
by XREAL_1:9;
then
m <= n
by A3, XXREAL_0:2;
then
(
P . m in the_Vertices_of GA &
P . n in the_Vertices_of GA )
by A3, A4, GLIB_001:8, XXREAL_0:2;
hence
contradiction
by A1, A2, A3, A5, Th19, Th40;
:: thesis: verum end;
hence
for m, n being natural odd number st m + 2 < n & n <= len P holds
for e being set holds not e Joins P . m,P . n,G
; :: thesis: verum