Originally Posted by

**chave** Hi,

Just a quick group theory question . . .

Q Let G := { x "element of" R : 0 <= x <1} and for x,y "element of" G.

Let x*y be the fractional part of x+y ie ( x*y = x+y - [x+y] where [n] is the greatest integer less than or equal to n. Show that * is a binary operation on G and G is abelian group under *.

Im just not sure what y can be , x has to be a real between 0 and 1, but it doesnt say about y only that is a part of G. also i assume the identity is 0???

and the inverse of x ????

thanks a million in advance

chave