Postprint version. Published in Proceedings of National Academy of Sciences of U.S.A, Volume 75, Issue 10, October 1, 1978, pages 4666-4667. Copyright © 1978 Proceedings of National Academy of Sciences of U.S.A.
NOTE: At the time of publication, the author Goro C. Kato was not yet affiliated with Cal Poly.
A second Leray spectral sequence of relative hypercohomology is constructed. (This is skew in generality to an earlier one constructed by S. Lubkin [(1968) Ann. Math. 87, 105-255].) The Mayer-Vietoris sequence of relative hypercohomology [Lubkin, S. (1968) Ann. Math. 87, 105-255] is also generalized.