On weak maps between 2-groups
| dc.creator | Noohi, Behrang | |
| dc.date | 2005-06-15 | |
| dc.date | 2008-07-13 | |
| dc.date.accessioned | 2026-07-07T09:49:43Z | |
| dc.date.available | 2026-07-07T09:49:43Z | |
| dc.description | We give an explicit handy (and cocycle-free) description of the groupoid of weak maps between two crossed-modules in terms of certain digrams of groups which we we call a {\em butterflies}. We define composition of butterflies and this way find a bicategory that is naturally biequivalent to the 2-category of pointed homotopy 2-types. We indicate how certain standard notions of 2-group theory (e.g., kernels, cokernels, extension of 2-groups, and so on) find a simple description in terms of butterflies. We also discuss braided and abelian butterflies. | |
| dc.description | A news section added and Section 9 expanded. Some minor errors corrected (and possibly new ones added). 48 pages | |
| dc.identifier | https://arxiv.org/abs/math/0506313 | |
| dc.identifier | http://arxiv.org/abs/math/0506313 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/164695 | |
| dc.subject | Category Theory | |
| dc.subject | Geometric Topology | |
| dc.subject | Quantum Algebra | |
| dc.title | On weak maps between 2-groups | |
| dc.type | text |