On the Seifert form at infinity associated with polynomial maps

If a polynomial map f : C(n) => C has a nice behaviour at infinity (e.g. it is a "good polynomial"), then the Milnor fibration at infinity exists; in particular, one can define the Seifert form at infinity -T(f) associated with f. In this paper we prove a Sebastiani-Thom type formula. Namely, if f :C(n)> C and g:C(m)> C are "good" polynomials, and we define h=f (+) g:C (n+m)>C by h(x,y)=f(x)+g(y), then T(h)=(-1)(mn) T (f) (*)T(g). This is the global analogue of the local result, proved independently by K. Sakamoto and P. Deligne for isolated hypersurface singularities.