English

A Menon-type Identity concerning Dirichlet characters and a generalization of the gcd function

Number Theory 2021-03-18 v3

Abstract

Menon's identity is a classical identity involving gcd sums and the Euler totient function ϕ\phi. In a recent paper, Zhao and Cao derived the Menon-type identity k=1n(k1,n)χ(k)=ϕ(n)τ(nd)\sum\limits_{\substack{k=1}}^{n}(k-1,n)\chi(k) = \phi(n)\tau(\frac{n}{d}), where χ\chi is a Dirichlet character mod nn with conductor dd. We derive an identity similar to this replacing gcd with a generalization it. We also show that some of the arguments used in the derivation of Zhao-Cao identity can be improved if one uses the method we employ here.

Cite

@article{arxiv.2005.12509,
  title  = {A Menon-type Identity concerning Dirichlet characters and a generalization of the gcd function},
  author = {Arya Chandran and Neha Elizabeth Thomas and K Vishnu Namboothiri},
  journal= {arXiv preprint arXiv:2005.12509},
  year   = {2021}
}
R2 v1 2026-06-23T15:48:36.159Z