{ "id": "1902.10012", "version": "v1", "published": "2019-02-26T15:50:34.000Z", "updated": "2019-02-26T15:50:34.000Z", "title": "Alternative versions of the Johnson homomorphisms and the LMO functor", "authors": [ "Anderson Vera" ], "comment": "62 pages, several figures", "categories": [ "math.GT" ], "abstract": "Let $\\Sigma$ be a compact connected oriented surface with one boundary component and let $\\mathcal{M}$ denote the mapping class group of $\\Sigma$. By considering the action of $\\mathcal{M}$ on the fundamental group of $\\Sigma$ it is possible to define different filtrations of $\\mathcal{M}$ together with some homomorphisms on each term of the filtration. The aim of this paper is twofold. Firstly we study a filtration of $\\mathcal{M}$ introduced recently by Habiro and Massuyeau, whose definition involves a handlebody bounded by $\\Sigma$. We shall call it the \"alternative Johnson filtration\", and the corresponding homomorphisms are referred to as \"alternative Johnson homomorphisms\". We provide a comparison between the alternative Johnson filtration and two previously known filtrations: the original Johnson filtration and the Johnson-Levine filtration. Secondly, we study the relationship between the alternative Johnson homomorphisms and the functorial extension of the Le-Murakami-Ohtsuki invariant of $3$-manifolds. We prove that these homomorphisms can be read in the tree reduction of the LMO functor. In particular, this provides a new reading grid for the tree reduction of the LMO functor.", "revisions": [ { "version": "v1", "updated": "2019-02-26T15:50:34.000Z" } ], "analyses": { "subjects": [ "57M27", "57M05", "57S05" ], "keywords": [ "lmo functor", "alternative versions", "alternative johnson homomorphisms", "alternative johnson filtration", "tree reduction" ], "note": { "typesetting": "TeX", "pages": 62, "language": "en", "license": "arXiv", "status": "editable" } } }