2025/11/28 by Wu, Hai-Liang, She, Yue-Feng
#FOS: Mathematics #Number Theory (math.NT)
paper · doi:10.48550/arxiv.2511.23223
In this paper, by using the arithmetic theory of ternary quadratic forms, we study some refinements on Lagrange's four-square theorem. For example, given positive integers a,b satisfying some algebraic conditions and a positive integer C≥3, we will show that for any sufficiently large integer n with \ord2(n)≤ C, there exist non-negative integers x,y,z,w such that \begincases x2+y2+z2+w2=n, ax+by\inS, \endcases where S is the set of all squares over ℤ. In particular, we obtain some progress on Zhi-Wei Sun's x+24y conjecture.