Y , X´Y , X, Y. , (, ).
1-10. ={1, 2}, Y={1, 3, 4}. X´Y ={(1,1), (1,3), (1,4), (2,1), (2,3), (2,4)}. . 1-9 .
1-11. Y . , . 1-9, 6. ,
. 1-9. .
. , ,
X´Y ¹Y´X.
. , r, , ..
,
X´Y=ÆC=Æ Y=Æ,
. =Æ , .
. s- s s , :
s=2, 3,... - 䒺 s,
.
R - , R2=R´R , R==R´R´R .