Abstract
In this paper, for the Green’s function of a bounded convex domain \(\Omega \) with pole at \(x_0\in \Omega \), we find the auxiliary curvature function which satisfies a differential inequality and so attains its minimum on the boundary. Moreover, we obtain a convexity estimate for the Green’s function of the domain above and give the proof of its specific convexity from the viewpoint of partial differential equations themselves.
Similar content being viewed by others
References
Acker, A., Payne, L.E., Philippin, G.: On the convexity of level lines of the fundamental mode in the clamped membrane problem, and the existence of convex solutions in a related free boundary problem. Z. Angew. Math. Phys. 32, 683–694 (1981)
Ahlfors L.V.: Conformal invariants: topics in geometric function theory. McGraw-Hill Series in Higher Mathematics, McGraw-Hill Book Co., New York-Dsseldorf-Johannesburg(1973).
Bian, B.J., Guan, P., Ma, X.N., Xu, L.: A constant rank theorem for quasiconcave solutions of fully nonlinear partial differential equations. Indiana Univ. Math. J. 60, 101–120 (2011)
Borell, C.: Hitting probabilities of killed Brownian motion: a study on geometric regularit. Ann. Sci. Ecole Norm. Sup. 17, 451–467 (1984)
Borell, C.: Geometric properties of some familiar diffusions in \({\mathbb{R}}^n\). Ann. Probab. 21, 482–489 (1993)
Brascamp, H.J., Lieb, E.H.: On extensions of the Brunn–Minkowski and Prekopa–Leindler theorems, including inequalities for log-concave functions, with an application to the diffusion equation. J. Funct. Anal. 22, 366–389 (1976)
Caffarelli, L., Guan, P., Ma, X.N.: A constant rank theorem for solutions of fully nonlinear elliptic equations. Comm. Pure Appl. Math. 60, 1769–1791 (2007)
Gabriel, R.: A result concerning convex level surfaces of 3-dimensional harmonic functions. J. London Math. Soc. 32, 286–294 (1957)
Gergen, J.: Note on the Green function of a star-shaped three dimensional region. Am. J. Math. 53, 746–752 (1931)
Guan P., Ma, X.N.: Convex solutions of fully nonlinear elliptic equations in classical differential geometry. Geometric evolution equations, pp. 115–127. Contemp. Math. 367, Am. Math. Soc. (2005)
Jost, J., Ma, X.N., Ou, Q.Z.: Curvature estimates in dimensions 2 and 3 for the level sets of p-harmonic functions in convex rings. Trans. AMS 364, 4605–4627 (2012)
Kawohl B.: Rearrangements and convexity of level sets in PDE. Lecture Notes in Math. 1150, Springer (1985)
Ma, X.N., Ou, Q.Z., Zhang, W.: Gaussian curvature estimates for the convex level sets of \(p\)-harmonic functions. Comm. Pure Appl. Math. 63, 935–971 (2010)
Ma, X.N., Shi, S.J., Ye, Y.: The convexity estimates for the solutions of two elliptic equations. Commun. Partial Diff. Equ. 37, 2116–2157 (2012)
Makar-Limanov, L.G.: Solution of Dirichlet’s problem for the equation \(\Delta u = -1\) on a convex region. Math. Notes Acad. Sci. USSR 9, 52–53 (1971)
Trudinger, N.S.: On new isoperimetric inequalities and symmetrization. J. Reine Angew. Math. 488, 203–220 (1997)
Acknowledgments
The author would like to express sincere gratitude to Prof. Xi-Nan Ma for his encouragement and many discussions in this subject. The author would also like to thank the referee for his (her) very careful reading and many good suggestions on this paper. Research of the author was supported in part by NSFC(No.11326144) and the Foundation of Harbin Normal University (No.KGB201224).
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by F. H. Lin.