A = { (x1 , x2) : 0<= x1<=1 and 0<= x2<=1}

B = { (y1, ,y2, y3) : (y1)^2 + (y2)^2 = 1 and 0<= y3<=1}

each with the usual toplogy.

Let f: A--->B be the funtion given by f(x1,x2) = (cos(2pi x1),sin (2pi x1), x2)

How do i give the explicit definition of the equivalence relation ~ on A ?

Any help is greatly apprecitated.