{ "id": "2209.06898", "version": "v1", "published": "2022-09-14T19:52:24.000Z", "updated": "2022-09-14T19:52:24.000Z", "title": "Borel complexity of modules", "authors": [ "Michael C. Laskowski", "Danielle S. Ulrich" ], "categories": [ "math.LO", "math.AC" ], "abstract": "We prove that for a countable, commutative ring $R$, the class of countable $R$-modules either has only countably many isomorphism types, or else it is Borel complete. The machinery gives a succinct proof of the Borel completeness of TFAB, the class of torsion-free abelian groups. We also prove that for any countable ring $R$, both the class of left $R$-modules endowed with an endomorphism and the class of left $R$-modules with four named submodules are Borel complete.", "revisions": [ { "version": "v1", "updated": "2022-09-14T19:52:24.000Z" } ], "analyses": { "subjects": [ "03E15", "13C05" ], "keywords": [ "borel complexity", "torsion-free abelian groups", "isomorphism types", "borel completeness", "succinct proof" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }