{ "id": "math/0202102", "version": "v3", "published": "2002-02-12T09:39:54.000Z", "updated": "2002-12-17T10:13:05.000Z", "title": "Torsion points on curves and common divisors of a^k-1 and b^k-1", "authors": [ "Nir Ailon", "Zeev Rudnick" ], "comment": "Conjecture B and Theorem 3 extended to the case of matrices with arbitrary determinant. Replaced the proof of Theorem 2 with a simpler one", "categories": [ "math.NT", "math.AG" ], "abstract": "We study the behavior of the greatest common divisor of a^k-1 and b^k-1, where a,b are fixed integers or polynomials, and k varies. In the integer case, we conjecture that when a and b are multiplicatively independent and in addition a-1 and b-1 are coprime, then a^k-1 and b^k-1 are coprime infinitely often. In the polynomial case, we prove a strong version of this conjecture. To do this we use a result of Lang's on the finiteness of torsion points on algebraic curves. We also give a matrix analogue of these results, where for a unimodular matrix A, we look at the greatest common divisor of the elements of the matrix A^k-I.", "revisions": [ { "version": "v3", "updated": "2002-12-17T10:13:05.000Z" } ], "analyses": { "subjects": [ "11D61" ], "keywords": [ "torsion points", "greatest common divisor", "integer case", "unimodular matrix", "conjecture" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2002math......2102A" } } }