arXiv subjects
Publications and source records attributed to Gennadiy Kalyabin.
Assuming the validity of Riemann Hypothesis (RH), we derive the explicit bilateral estimates ("narrow passage") of the remainder in the modified Mertens asymptotic formula for the sums of primes' reciprocals. These results are reversable, thus yielding some new criteria for RH.
A highly strong upper estimate in the modified asymptotic formula for sums of the primes' reciprocals is proved to be necessary (as well as sufficient) in order the Ramanujan inequality holds true. Some other criteria in similar terms are also obtained.
The infinitude is established of the set ${\bf U_1}$ of positive integers $N>5$ such that $G(N)\le \min(G(N/q), G(Np))$ where $q, p$ are primes, $q\ | N$ and $G(N):=\frac{σ(N)}{N\log \log N}$ stands for Gronwall number, $σ(N)$ being the sum of all divisors of $N$. The constructive algorithm is proposed which successively calculates the elements of ${\bf U_1}$, the least of them $N_1^*=2^5\cdot 3^3 \cdot 5^2 \cdot 7 \cdot 11 \cdot 13 \cdot 17 \cdot 19 \cdot 23 =160\ 626\ 866\ 400, \ G(N_1^*)=1.7374\dots$ Some interesting properties of these numbers are studied which may occur useful for the proof of Ramanujan-Robin inequality.