{ "id": "2212.14139", "version": "v1", "published": "2022-12-29T00:49:33.000Z", "updated": "2022-12-29T00:49:33.000Z", "title": "The matrix equation $aX^m+bY^n=cI$ over $M_2(\\mathbb{Z})$", "authors": [ "Hongjian Li", "Pingzhi Yuan" ], "categories": [ "math.NT" ], "abstract": "Let $\\mathbb{N}$ be the set of all positive integers and let $a,\\, b,\\, c$ be nonzero integers such that $\\gcd\\left(a,\\, b,\\, c\\right)=1$. In this paper, we prove the following three results: (1) the solvability of the matrix equation $aX^m+bY^n=cI,\\,X,\\,Y\\in M_2(\\mathbb{Z}),\\, m,\\, n\\in\\mathbb{N}$ can be reduced to the solvability of the corresponding Diophantine equation if $XY\\neq YX$ and the solvability of the equation $ax^m+by^n=c,\\, m,\\, n\\in\\mathbb{N}$ in quadratic fields if $XY=YX$; (2) we determine all non-commutative solutions of the matrix equation $X^n+Y^n=c^nI,\\,X,\\,Y\\in M_2(\\mathbb{Z}),\\,n\\in\\mathbb{N},\\,n\\geq3$, and the solvability of this matrix equation can be reduced to the solvability of the equation $x^n+y^n=c^n,\\, n\\in\\mathbb{N},\\,n\\geq3$ in quadratic fields if $XY=YX$; (3) we determine all solutions of the matrix equation $aX^2+bY^2=cI,\\,X,\\,Y\\in M_2(\\mathbb{Z})$.", "revisions": [ { "version": "v1", "updated": "2022-12-29T00:49:33.000Z" } ], "analyses": { "subjects": [ "15A20", "15A24", "15B36", "11D09", "11D41" ], "keywords": [ "matrix equation", "solvability", "quadratic fields", "corresponding diophantine equation", "nonzero integers" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }