(G;x) is a group ( e it's identity element). and are a subgroups from (G,x).
={ / } x }
1)-I must show that : is a subgroup from(G;x)
2)- We assume that and are finished and ={e} and:
: x
( ; )
I must show that is surjective and Card( )=Card( )Card( )
I don't know anything!!!!!!! Can you give me some help please????