let p be natural prime number ; for G being finite Group
for H being Subgroup of G st G is p -group holds
expon H,p <= expon G,p
let G be finite Group; for H being Subgroup of G st G is p -group holds
expon H,p <= expon G,p
let H be Subgroup of G; ( G is p -group implies expon H,p <= expon G,p )
assume A1:
G is p -group
; expon H,p <= expon G,p
then
card G = p |^ (expon G,p)
by def2;
then
ex r being natural number st
( card H = p |^ r & r <= expon G,p )
by GROUP_2:178, Th2;
hence
expon H,p <= expon G,p
by A1, def2; verum