{ "id": "1707.01485", "version": "v1", "published": "2017-07-05T17:34:47.000Z", "updated": "2017-07-05T17:34:47.000Z", "title": "On free resolutions of Iwasawa modules", "authors": [ "Alexandra Nichifor", "Bharathwaj Palvannan" ], "comment": "39 pages. Comments welcome", "categories": [ "math.NT" ], "abstract": "Let $\\Lambda$ (isomorphic to $\\mathbb{Z}_p[[T]]$) denote the usual Iwasawa algebra and $G$ denote the Galois group of a finite Galois extension $L/K$ of totally real fields. The main theorems in this article describe the precise conditions under which non-primitive Iwasawa modules, over the cyclotomic $\\mathbb{Z}_p$-extension, have a free resolution of length one over the group ring $\\Lambda[G]$. As one application, under these conditions of the main theorems, the validity of the non-commutative Iwasawa main conjecture allows us to find a representative for the non-primitive $p$-adic $L$-function (which is an element of a $K_1$-group) in a maximal $\\Lambda$-order. As another application, we consider an elliptic curve over $\\mathbb{Q}$ with a cyclic isogeny of degree $p^2$. We relate the characteristic ideal, in the ring $\\Lambda$, of the Pontryagin dual of its non-primitive Selmer group to two characteristic ideals, viewed as elements of group rings over $\\Lambda$, associated to two non-primitive classical Iwasawa modules.", "revisions": [ { "version": "v1", "updated": "2017-07-05T17:34:47.000Z" } ], "analyses": { "subjects": [ "11R23", "11R34", "11S25" ], "keywords": [ "iwasawa modules", "free resolution", "characteristic ideal", "main theorems", "usual iwasawa algebra" ], "note": { "typesetting": "TeX", "pages": 39, "language": "en", "license": "arXiv", "status": "editable" } } }