Log-convexity and log-concavity of hypergeometric-like functions

D. Karp, S. M. Sitnik

We find sufficient conditions for log-convexity and log-concavity for the functions of the forms $a\mapsto \sum f_k(a{)}_k{x}^k$, $a\mapsto \sum f_k\Gamma (a+k)x^k$ and $a\mapsto\sum{f_k}x^k…