2025/08/11 by Kim, Daejun
#11E12 #11E20 #11E25 #FOS: Mathematics #Number Theory (math.NT)
paper · doi:10.48550/arxiv.2508.08106
A subset A⊆ℤ is called s-almost square universal if every sufficiently large positive integer can be written as a sum of at most s squares of integers from A. In this article, we study the minimal number ASU(Ad,m) with this property, where Ad,m denotes the residue class of d modulo m, with m∈ℕ and d∈ℤ. We further prove that Ad,m is s-square universal for some s∈ℕ if and only if d ≡ ± 1 \pmodm, and determine the minimal such number SU(Ad,m) in these cases.