Abstract
In this paper, we continue the study of critical sets of solutions \(u_{\varepsilon }\) of second-order elliptic equations in divergence form with rapidly oscillating and periodic coefficients. In [18], by controlling 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 \(\varepsilon \), 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 \(u_{\varepsilon }\), 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.
Similar content being viewed by others
References
Alessandrini, G., Magnanini, R.: Elliptic equations in divergence form, geometric critical points of solutions and Stekloff eigenfunctions. SIAM J. Math. Anal. 25, 1259–1268 (1994)
Alessandrini, G., Nesi, V.: Univalent \(\sigma \)-harmonic mappings. Arch. Ration. Mech. Anal. 158, 155–171 (2001)
Alessandrini, G., Nesi, V.: Locally invertible \(\sigma \)-harmonic mappings. Rend. Mat. Appl. (7) 39, 195–203 (2018)
Alessandrini, G., Nesi, V.: Globally diffeomorphic \(\sigma \)-harmonic mappings. Ann. Mat. Pura Appl. (4) 200, 1625–1635 (2021)
Badger, M., Engelstein, M., Toro, T.: Structure of sets which are well approximated by zero sets of harmonic polynomials. Anal. PDE 10, 1455–1495 (2017)
Bauman, P., Marini, A., Nesi, V.: Univalent solutions of an elliptic system of partial differential equations arising in homogenization. Indiana Univ. Math. J. 50, 747–757 (2001)
Briane, M., Milton, G.W., Nesi, V.: Change of sign of the corrector’s determinant for homogenization in three-dimensional conductivity. Arch. Ration. Mech. Anal. 173, 133–150 (2004)
Capdeboscq, Y.: On a counter-example to quantitative Jacobian bounds. J. Éc. polytech. Math. 2, 171–178 (2015)
Cheeger, J., Naber, A., Valtorta, D.: Critical sets of elliptic equations. Commun. Pure Appl. Math. 68, 173–209 (2015)
Donnelly, H., Fefferman, C.: Nodal sets of eigenfunctions on Riemannian manifolds. Invent. Math. 93, 161–183 (1988)
Han, Q.: Singular sets of solutions to elliptic equations. Indiana Univ. Math. J. 43, 983–1002 (1994)
Han, Q., Hardt, R., Lin, F.: Geometric measure of singular sets of elliptic equations. Commun. Pure Appl. Math. 51, 1425–1443 (1998)
Han, Q., Lin, F.: On the geometric measure of nodal sets of solutions. J. Partial Differ. Equ. 7, 111–131 (1994)
Hardt, R., Hoffmann-Ostenhof, M., Hoffmann-Ostenhof, T., Nadirashvili, N.: Critical sets of solutions to elliptic equations. J. Differ. Geom. 51, 359–373 (1999)
Hardt, R., Simon, L.: Nodal sets for solutions of elliptic equations. J. Differ. Geom. 30, 505–522 (1989)
Lin, F.: Nodal sets of solutions of elliptic and parabolic equations. Commun. Pure Appl. Math. 44, 287–308 (1991)
Lin, F., Shen, Z.: Nodal sets and doubling conditions in elliptic homogenization. Acta Math. Sin. English. Ser. 35, 815–831 (2019)
Lin, F., Shen, Z.: Critical sets of solutions of elliptic equations in periodic homogenization. arXiv:2203.13393v1 (2022)
Logunov, A.: Nodal sets of Laplace eigenfunctions: polynomial upper estimates of the Hausdorff measure. Ann. Math. (2) 187, 221–239 (2018)
Logunov, A.: Nodal sets of Laplace eigenfunctions: proof of Nadirashvili’s conjecture and of the lower bound in Yau’s conjecture. Ann. Math. (2) 187, 241–262 (2018)
Naber, A., Valtorta, D.: Volume estimates on the critical sets of solutions to elliptic PDEs. Commun. Pure Appl. Math. 70, 1835–1897 (2017)
Acknowledgements
Fanghua Lin is supported in part by NSF grant DMS-1955249. Zhongwei Shen is supported in part by NSF grant DMS-1856235 and by Simons Fellowship.
Author information
Authors and Affiliations
Corresponding author
Additional information
Dedicated to our teacher Professor Carlos Kenig on the occasion of his 70th birthday.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Lin, F., Shen, Z. Critical Sets of Elliptic Equations with Rapidly Oscillating Coefficients in Two Dimensions. Vietnam J. Math. 51, 951–961 (2023). https://doi.org/10.1007/s10013-023-00632-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10013-023-00632-4