On Characterizations of Convex and Approximately Subadditive Sequences

Angshuman Robin Goswami

A sequence $(u_n{)}_{n=0}^{\infty }$ is said to be convex if it satisfies the following inequality $$ 2u_n\leq u_{n-1}+u_{n+1}\qquad \mbox{for all}\qquad n\in\mathbb{N}. $$ We…