let G be _Graph; 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 odd Nat st m + 2 < n & n <= len W holds
for e being object holds not e Joins W . m,W . n,G
let S be 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 odd Nat st m + 2 < n & n <= len W holds
for e being object holds not e Joins W . m,W . n,G
let GA be inducedSubgraph of G,S; for W being Walk of GA st W is minlength holds
for m, n being odd Nat st m + 2 < n & n <= len W holds
for e being object holds not e Joins W . m,W . n,G
let P be Walk of GA; ( P is minlength implies for m, n being odd Nat st m + 2 < n & n <= len P holds
for e being object holds not e Joins P . m,P . n,G )
A1:
S = the_Vertices_of GA
by GLIB_000:def 37;
assume A2:
P is minlength
; for m, n being odd Nat st m + 2 < n & n <= len P holds
for e being object holds not e Joins P . m,P . n,G
now for m, n being odd Nat st m + 2 < n & n <= len P holds
for e being object holds not e Joins P . m,P . n,Glet m,
n be
odd Nat;
( m + 2 < n & n <= len P implies for e being object holds not e Joins P . m,P . n,G )assume that A3:
m + 2
< n
and A4:
n <= len P
;
for e being object holds not e Joins P . m,P . n,G
m + 0 <= m + 2
by XREAL_1:7;
then A5:
m <= n
by A3, XXREAL_0:2;
n in NAT
by ORDINAL1:def 12;
then A6:
P . n in the_Vertices_of GA
by A4, GLIB_001:7;
m in NAT
by ORDINAL1:def 12;
then A7:
P . m in the_Vertices_of GA
by A4, A5, GLIB_001:7, XXREAL_0:2;
let e be
object ;
not e Joins P . m,P . n,Gassume
e Joins P . m,
P . n,
G
;
contradictionhence
contradiction
by A2, A1, A3, A4, A7, A6, Th19, Th39;
verum end;
hence
for m, n being odd Nat st m + 2 < n & n <= len P holds
for e being object holds not e Joins P . m,P . n,G
; verum