{ "id": "2204.02532", "version": "v1", "published": "2022-04-06T01:16:07.000Z", "updated": "2022-04-06T01:16:07.000Z", "title": "Critical Sets of Elliptic Equations with Rapidly Oscillating Coefficients in Two Dimensions", "authors": [ "Fanghua Lin", "Zhongwei Shen" ], "comment": "12 pages. arXiv admin note: text overlap with arXiv:2203.13393", "categories": [ "math.AP" ], "abstract": "In this paper we continue the study of critical sets of solutions $u_\\e$ of second-order elliptic equations in divergence form with rapidly oscillating and periodic coefficients. In \\cite{Lin-Shen-3d}, by controling the \"turning\" of approximate tangent planes, we show that the $(d-2)$-dimensional Hausdorff measures of the critical sets are bounded uniformly with respect to the period $\\e$, provided that doubling indices for solutions are bounded. In this paper we use a different approach, based on the reduction of the doubling indices of $u_\\e$, to study the two-dimensional case. The proof relies on the fact that the critical set of a homogeneous harmonic polynomial of degree two or higher in dimension two contains only one point.", "revisions": [ { "version": "v1", "updated": "2022-04-06T01:16:07.000Z" } ], "analyses": { "subjects": [ "35J15", "35B27" ], "keywords": [ "critical set", "rapidly oscillating coefficients", "dimensional hausdorff measures", "doubling indices", "approximate tangent planes" ], "note": { "typesetting": "TeX", "pages": 12, "language": "en", "license": "arXiv", "status": "editable" } } }