{ "id": "0804.2833", "version": "v1", "published": "2008-04-17T15:20:30.000Z", "updated": "2008-04-17T15:20:30.000Z", "title": "Inequalities of Hardy-Sobolev type in Carnot-Carathéodory spaces", "authors": [ "Donatella Danielli", "Nicola Garofalo", "Nguyen Cong Phuc" ], "comment": "31 pages", "categories": [ "math.AP" ], "abstract": "We consider various types of Hardy-Sobolev inequalities on a Carnot-Carath\\'eodory space $(\\Om, d)$ associated to a system of smooth vector fields $X=\\{X_1, X_2,...,X_m\\}$ on $\\RR^n$ satisfying the H\\\"ormander's finite rank condition $rank Lie[X_1,...,X_m] \\equiv n$. One of our main concerns is the trace inequality \\int_{\\Om}|\\phi(x)|^{p}V(x)dx\\leq C\\int_{\\Om}|X\\phi|^{p}dx,\\qquad \\phi\\in C^{\\infty}_{0}(\\Om), where $V$ is a general weight, i.e., a nonnegative locally integrable function on $\\Om$, and $1