Intersection homology Kunneth theorems

Cohen, Goresky, and Ji showed that there is a Künneth theorem relating the intersection homology groups Mathematic expression, provided that the perversity Mathematic expression satisfies rather strict conditions. We consider biperversities and prove that there is a Künneth theorem relating Mathematic expression for all choices of Mathematic expression. Furthermore, we prove that the Künneth theorem still holds when the biperversity p, q is "loosened" a little, and using this we recover the Künneth theorem of Cohen-Goresky-Ji. © 2008 Springer-Verlag.