On piecewise isomorphism of some varieties

Two quasi-projective varieties are called piecewise isomorphic if they can be stratified into pairwise isomorphic strata. We show that the m-th symmetric power Sm(Cn) of the complex affine space Cn is piecewise isomorphic to Cmn and the m-th symmetric power Sm(CP∞ ) of the infinite dimensional complex projective space is piecewise isomorphic to the infinite dimensional Grassmannian Gr(m;∞).