{ "id": "math/0603383", "version": "v2", "published": "2006-03-15T19:41:09.000Z", "updated": "2006-11-14T16:11:22.000Z", "title": "Nested set complexes of Dowling lattices and complexes of Dowling trees", "authors": [ "Emanuele Delucchi" ], "comment": "14 pages, 2 figures, corrected typos, added references", "categories": [ "math.CO", "math.AT" ], "abstract": "Given a finite group G and a natural number n, we study the structure of the complex of nested sets of the associated Dowling lattice Q(G) and of its subposet of the G-symmetric partitions Q_G which was recently introduced by Hultman together with the complex of G-symmetric phylogenetic trees T_G. Hultman shows that T_G and Q_G are homotopy equivalent and Cohen-Macaulay, and determines the rank of their top homology. An application of the theory of building sets and nested set complexes by Feichtner and Kozlov shows that in fact T_G is subdivided by the order complex of Q_G. We introduce the complex of Dowling trees T(G) and prove that it is subdivided by the order complex of Q(G) and contains T_G as a subcomplex. We show that T(G) is obtained from T_G by successive coning over certain subcomplexes. We explicitly and independently calculate how many homology spheres are added in passing from T_G to T(G).", "revisions": [ { "version": "v2", "updated": "2006-11-14T16:11:22.000Z" } ], "analyses": { "subjects": [ "37F20" ], "keywords": [ "nested set complexes", "dowling trees", "dowling lattice", "order complex", "g-symmetric phylogenetic trees" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006math......3383D" } } }