Abstract:
The theory of subharmonic functions of finite order is based to a considerable
extent on integral formulae. In the present paper representations are obtained for subharmonic
functions in the upper half-plane with more general growth $\gamma(r)$ than finite order.
The main result can be stated as follows. Let $\gamma(r)$ be a growth function such that
either $\ln\gamma(r)$ is a convex function of $\ln r$ or the lower order of $\gamma(r)$ is infinite. Then for each proper subharmonic function $v$ of growth $\gamma(r)$ there exist an unbounded set $\mathbf R$ of positive numbers and a family
$\{u_R:R\in\mathbf R\}$ of proper subharmonic functions in the upper
half-plane $\mathbb{C}_+$ such that
1) the full measures of the $u_R$ in the discs $|z|\leqslant R$
are equal to the full measure of the function $v$;
2) $v-u_R\rightrightarrows0$ uniformly on compact subsets of $\mathbb{C}_+$
as $R\to\infty$, $R\in\mathbf R$;
3) the function family
$\{u_R:R\in\mathbf R\}$ satisfies the growth constraints uniformly in $R$,
that is, $T(r,u_R)\leqslant A\gamma(Br)/r$, where $A$ and $B$ are constants
and $T(r,\,\cdot\,)$ is the growth characteristic.
Bibliography: 16 titles.