SL(2,Z) modular forms and anomaly cancellation formulas for almost complex manifolds

Abstract

In this paper, we define a generalized elliptic genus of an almost complex manifold with an extra complex bundle which generalize the elliptic genus in [10]. This generalized elliptic genus is a generalized Jacobi form. By this generalized Jacobi form, we can get some SL(2,Z) modular forms. By these SL(2,Z) modular forms, we get some interesting anomaly cancellation formulas for an almost complex manifold . As corollaries, we get some divisibility results of the holomorphic Euler characteristic number.