Totient inequality at consecutive integers is still open
Establish whether there exist infinitely many primes p such that Euler’s totient function satisfies φ(p+1) > φ(p).
References
We have a conjecture that, for infinitely many primes $p$, $\varphi(p+1) > \varphi(p)$, this conjecture is still open.
— Divisibility and Sequence Properties of $σ^+$ and $\varphi^+$
(2508.11660 - Mandal, 6 Aug 2025) in Section 2, Main Results (preceding Lemma on φ⁺(q)<φ⁺(q+1))