{ "id": "1708.07683", "version": "v1", "published": "2017-08-25T10:42:37.000Z", "updated": "2017-08-25T10:42:37.000Z", "title": "A radial invariance principle for non-homogeneous random walks", "authors": [ "Nicholas Georgiou", "Aleksandar Mijatović", "Andrew R. Wade" ], "comment": "10 pages", "categories": [ "math.PR" ], "abstract": "Consider non-homogeneous zero-drift random walks in $\\mathbb{R}^d$, $d \\geq 2$, with the asymptotic increment covariance matrix $\\sigma^2 (\\mathbf{u})$ satisfying $\\mathbf{u}^\\top \\sigma^2 (\\mathbf{u}) \\mathbf{u} = U$ and $\\mathrm{tr}\\ \\sigma^2 (\\mathbf{u}) = V$ in all in directions $\\mathbf{u}\\in\\mathbb{S}^{d-1}$ for some positive constants $U