LAUSR

Abstract B. Sury proved the following Menon-type identity, ∑ a ∈ U ( Z n ) , b 1 , ⋯ , b r ∈ Z n gcd ⁡ ( a − 1 , b 1 , ⋯ , b r , n ) = φ ( n ) σ r ( n ) , where U ( Z n ) is the group of units of the ring for residual classes modulo n, φ is the Euler's totient function and σ r ( n ) is the sum of r-th powers of positive divisors of n with r being a non-negative integer. Recently, C. Miguel extended this identity from Z to any residually finite Dedekind domain. In this note, we will give a further extension of Miguel's result to the case with many tuples of group of units. For the case of Z , our result reads as follows ∑ a 1 , ⋯ , a s ∈ U ( Z n ) , b 1 , ⋯ , b r ∈ Z n gcd ⁡ ( a 1 − 1 , ⋯ , a s − 1 , b 1 , ⋯ , b r , n ) = φ ( n ) ∏ i = 1 m ( φ ( p i k i ) s − 1 p i k i r − p i k i ( s + r − 1 ) + σ s + r − 1 ( p i k i ) ) , where n = p 1 k 1 ⋯ p m k m is the prime factorization of n.