Half a century after the appearance of the celebrated paper by Serrin about overdetermined boundary value problems in potential theory and related symmetry properties, we reconsider semilinear polyharmonic equations under Dirichlet boundary conditions in the unit ball of $ \mathbb{R}^{n} $. We discuss radial properties (symmetry and monotonicity) of positive solutions of such equations and we show that, in conformal dimensions, the associated Green function satisfies elegant reflection and symmetry properties related to a suitable Kelvin transform (inversion about a sphere). This yields an alternative formula for computing the partial derivatives of solutions of polyharmonic problems. Moreover, it gives some hints on how to modify a counterexample by Sweers where radial monotonicity fails: we numerically recover strict radial monotonicity for the biharmonic equation in the unit ball of $ \mathbb{R}^{4} $.
Citation: Filippo Gazzola, Gianmarco Sperone. Remarks on radial symmetry and monotonicity for solutions of semilinear higher order elliptic equations[J]. Mathematics in Engineering, 2022, 4(5): 1-24. doi: 10.3934/mine.2022040
Half a century after the appearance of the celebrated paper by Serrin about overdetermined boundary value problems in potential theory and related symmetry properties, we reconsider semilinear polyharmonic equations under Dirichlet boundary conditions in the unit ball of $ \mathbb{R}^{n} $. We discuss radial properties (symmetry and monotonicity) of positive solutions of such equations and we show that, in conformal dimensions, the associated Green function satisfies elegant reflection and symmetry properties related to a suitable Kelvin transform (inversion about a sphere). This yields an alternative formula for computing the partial derivatives of solutions of polyharmonic problems. Moreover, it gives some hints on how to modify a counterexample by Sweers where radial monotonicity fails: we numerically recover strict radial monotonicity for the biharmonic equation in the unit ball of $ \mathbb{R}^{4} $.
[1] | A. D. Alexandrov, Uniqueness theorem for surfaces in the large, Vestnik Leningradskogo Universiteta, 11 (1956), 5–17. |
[2] | A. D. Alexandrov, A characteristic property of spheres, Annali di Matematica, 58 (1962), 303–315. doi: 10.1007/BF02413056 |
[3] | E. Berchio, F. Gazzola, T. Weth, Radial symmetry of positive solutions to nonlinear polyharmonic Dirichlet problems, J. reine angew. Math., 620 (2008), 165–183. |
[4] | H. Berestycki, L. Nirenberg, On the method of moving planes and the sliding method, Bol. Soc. Bras. Mat., 22 (1991), 1–37. doi: 10.1007/BF01244896 |
[5] | T. Boggio, Sulle funzioni di Green d'ordine m, Rend. Circ. Matem. Palermo, 20 (1905), 97–135. doi: 10.1007/BF03014033 |
[6] | R. Dalmasso, Symmetry properties in higher order semilinear elliptic equations, Nonlinear Anal. Theor., 24 (1995), 1–7. doi: 10.1016/0362-546X(94)E0030-K |
[7] | R. Dalmasso, Existence and uniqueness results for polyharmonic equations, Nonlinear Anal. Theor., 36 (1999), 131–137. doi: 10.1016/S0362-546X(98)00049-2 |
[8] | F. Gazzola, H.-C. Grunau, Radial entire solutions for supercritical biharmonic equations, Math. Ann., 334 (2006), 905–936. doi: 10.1007/s00208-005-0748-x |
[9] | F. Gazzola, H.-C. Grunau, G. Sweers, Polyharmonic boundary value problems: positivity preserving and nonlinear higher order elliptic, Springer Science & Business Media, 2010. |
[10] | B. Gidas, W.-M. Ni, L. Nirenberg, Symmetry and related properties via the maximum principle, Commun. Math. Phys., 68 (1979), 209–243. doi: 10.1007/BF01221125 |
[11] | H.-C. Grunau, G. Sweers, Positivity for equations involving polyharmonic operators with Dirichlet boundary conditions, Math. Ann., 307 (1996), 589–626. |
[12] | H.-C. Grunau, G. Sweers, Positivity properties of elliptic boundary value problems of higher order, Nonlinear Anal. Theor., 30 (1997), 5251–5258. doi: 10.1016/S0362-546X(96)00164-2 |
[13] | S. Mayboroda, V. Maz'ya, Regularity of solutions to the polyharmonic equation in general domains, Invent. Math., 196 (2014), 1–68. doi: 10.1007/s00222-013-0464-1 |
[14] | C. Nitsch, C. Trombetti, The classical overdetermined Serrin problem, Complex Var. Elliptic Equ., 63 (2018), 1107–1122. doi: 10.1080/17476933.2017.1410798 |
[15] | J. Serrin, A symmetry problem in potential theory, Arch. Rational Mech. Anal., 43 (1971), 304–318. doi: 10.1007/BF00250468 |
[16] | G. Sweers, No Gidas-Ni-Nirenberg type result for semilinear biharmonic problems, Math. Nachr., 246 (2002), 202–206. |
[17] | W. C. Troy, Symmetry properties in systems of semilinear elliptic equations, J. Differ. Equations, 42 (1981), 400–413. doi: 10.1016/0022-0396(81)90113-3 |
[18] | H. F. Weinberger, Remark on the preceding paper of Serrin, Arch. Rational Mech. Anal., 43 (1971), 319–320. doi: 10.1007/BF00250469 |