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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).

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Background

The authors explicitly note the longstanding conjecture that φ(p+1) > φ(p) for infinitely many primes p remains unresolved. They then provide an analogous result for the modified function φ⁺(n) for a specific infinite subsequence of primes.

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))