On the sign changes of Dirichlet coefficients of triple product L-functions

Let f and g be two distinct normalized primitive holomorphic cusp forms of even integral weight k(1) and k(2) for the full modular group SL(2,Z), respectively. Suppose that lambda(fxfxf)(n) and lambda(gxgxg)(n) are the n-th Dirichlet coefficient of the triple product L-functions L(s,(fxfxf)) and L(s,(gxgxg)). In this paper, we consider the sign changes of the sequence {lambda(fxfxf)(n)}(n >= 1) and {lambda(fxfxf)(n)lambda(gxgxg)(n)}(n >= 1) in short intervals and establish quantitative results for the number of sign changes for n <= x, which improve the previous results.