{ "id": "math/0412438", "version": "v1", "published": "2004-12-21T19:23:52.000Z", "updated": "2004-12-21T19:23:52.000Z", "title": "The boundary of the moduli space of quadratic rational maps", "authors": [ "Laura DeMarco" ], "comment": "38 pages, 3 figures", "categories": [ "math.DS", "math.AG" ], "abstract": "Let $M_2$ be the space of quadratic rational maps $f:{\\bf P}^1\\to{\\bf P}^1$, modulo the action by conjugation of the group of M\\\"obius transformations. In this paper a compactification $X$ of $M_2$ is defined, as a modification of Milnor's $\\bar{M}_2\\iso{\\bf CP}^2$, by choosing representatives of a conjugacy class $[f]\\in M_2$ such that the measure of maximal entropy of $f$ has conformal barycenter at the origin in ${\\bf R}^3$, and taking the closure in the space of probability measures. It is shown that $X$ is the smallest compactification of $M_2$ such that all iterate maps $[f]\\mapsto [f^n]\\in M_{2^n}$ extend continuously to $X \\to \\bar{M}_{2^n}$, where $\\bar{M}_d$ is the natural compactification of $M_d$ coming from geometric invariant theory.", "revisions": [ { "version": "v1", "updated": "2004-12-21T19:23:52.000Z" } ], "analyses": { "subjects": [ "37F45" ], "keywords": [ "quadratic rational maps", "moduli space", "geometric invariant theory", "natural compactification", "iterate maps" ], "note": { "typesetting": "TeX", "pages": 38, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2004math.....12438D" } } }