On certain sums of arithmetic functions involving the gcd and lcm of two positive integers

Abstract

We obtain asymptotic formulas with remainder terms for the hyperbolic summations ${\sum }_{mn\le x}f((m,n))$ and ${\sum }_{mn\le x}f([m,n])$, where $f$ belongs to certain classes of arithmetic functions, $(m,n)$ and $[m,n]$ denoting the gcd and lcm of the integers $m,n$. In particular, we investigate the functions $f(n)=\tau (n),\log n,\omega (n)$ and $\Omega (n)$. We also define a common generalization of the latter three functions, and prove a corresponding result.

21 pages, revised