A definition of wedge sum can be found here:

http://en.wikipedia.org/wiki/Wedge_sum

My professor has claimed that wedge sums of path connected spaces X and Y are well-defined up to homotopy equivalence, independently of choice of base points x0 and y0. Base point here means the points that are identified under the equivalence relation forming the wedge product out of the disjoint union topology of X and Y.

Recall homotopy equivalence of X and Y means that there is f:X->Y and g:Y->X continuous with gf and fg homotopic to the identity.

With these definitions, please prove my professor's claim, which I have failed to do for a week. (It is left as an exercise in his lecture.)

Thanks.