Well-behaved Beurling primes and integers

In this paper, we study generalised prime systems for which both the prime and integer counting functions are asymptotically well-behaved, in the sense that they are approximately li(x) and ρx, respectively (where ρ is a positive constant), with error terms of order O(xθ1) and O(xθ2) for some θ1,θ2<1. We show that it is impossible to have both θ1 and θ2 less than 12.