{ "id": "1711.00230", "version": "v1", "published": "2017-11-01T07:22:41.000Z", "updated": "2017-11-01T07:22:41.000Z", "title": "On the $Γ$-equivalence of binary quadratic forms", "authors": [ "Bumkyu Cho" ], "comment": "submitted for publication", "categories": [ "math.NT" ], "abstract": "For a congruence subgroup $\\Gamma$, we define the notion of $\\Gamma$-equivalence on binary quadratic forms which is the same as proper equivalence if $\\Gamma = \\mathrm{SL}_2(\\mathbb Z)$. We develop a theory on $\\Gamma$-equivalence such as the finiteness of $\\Gamma$-reduced forms, the isomorphism between $\\Gamma_0(N)$-form class group and the ideal class group, $N$-representation of integers, and $N$-genus of binary quadratic forms. As an application, we deal with representations of integers by binary quadratic forms under certain congruence condition on variables.", "revisions": [ { "version": "v1", "updated": "2017-11-01T07:22:41.000Z" } ], "analyses": { "subjects": [ "11E16", "11E25", "11R29" ], "keywords": [ "binary quadratic forms", "ideal class group", "form class group", "representation", "proper equivalence" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }