let G be Group; for H being Subgroup of G st the carrier of G c= the carrier of H holds
multMagma(# the carrier of H, the multF of H #) = multMagma(# the carrier of G, the multF of G #)
let H be Subgroup of G; ( the carrier of G c= the carrier of H implies multMagma(# the carrier of H, the multF of H #) = multMagma(# the carrier of G, the multF of G #) )
assume A1:
the carrier of G c= the carrier of H
; multMagma(# the carrier of H, the multF of H #) = multMagma(# the carrier of G, the multF of G #)
A2:
G is Subgroup of G
by Th63;
the carrier of H c= the carrier of G
by Def5;
then
the carrier of G = the carrier of H
by A1, XBOOLE_0:def 10;
hence
multMagma(# the carrier of H, the multF of H #) = multMagma(# the carrier of G, the multF of G #)
by A2, Th68; verum