On a countable base and the conjugate class of a topological space

In this paper the classes $\varphi (L)$ of functions are studied, and the topological spaces $U_\varphi$ are constructed from them. In particular, a necessary and sufficient condition guaranteeing a countable base in $U_\varphi$ is found. Classes $\overline\varphi (L)$ of functions conjugate (relative to sum) to $\varphi (L)$ are introduced and investigated.
Bibliography: 7 titles.