Could anyone tell me in what sense the following is an "asymptotic formula":
Theorem 1 from
(this is open access, so I think I'm allowed to link it)
At the moment, I'm just trying to understand what the bit with $Q\leq x$ means. I assume the Theorem says something like: the LHS varies like the main term, in that LHS/[main term] tends to one as x tends to infinity. But it's not clear to me that [error terms]/[main terms] tend to zero. There seems to be definitely something I'm not understanding with the relationship between $Q$ and $x$.
Can anyone clarify?
Thanks very much.