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The set of positive solutions of semilinear equations in large balls

Published online by Cambridge University Press:  14 November 2011

R. Gardner
Affiliation:
Department of Mathematics, University of Massachusetts, Amherst, MA 01003, U.S.A.
L. A. Peletier
Affiliation:
Mathematical Institute, University of Leiden, Niels Bohrweg 1, Postbus 9512, 2300 RA Leiden, The Netherlands

Synopsis

The exact number of positive solutions of Δu + f(u) = 0 on finite balls in N is determined. The assumptions about f(u) are similar to those imposed by Serrin and the second author in a previous study of uniqueness of the positive solution when the spatial domain is all of N (see [7, 8]). For finite balls of sufficiently large radius it is shown here that there are exactly two positive and, hence, radial solutions. To this end, we first prove the linear nondegeneracy of the positive solution of N. This is obtained by applying the technique of monotone separation of graphs [7] to the linearised equations. Somewhat sharper estimates are required here (see Part I, Section 2).

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1986

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References

1Angenent, S.. Uniqueness of the solution of a semilinear boundary value problem. Math. Annalen 272 (1985), 129138.Google Scholar
2Atkinson, F V. and Peletier, L. A.. Ground states of − Δu = f(u) and the Emden-Fowler equation. Arch. Rational Mech. Anal. 93 (1986), 103127.Google Scholar
3Berestycki, H., Lions, P. L. and Peletier, L. A.. An ODE approach to the existence of positive solutions for semilinear problems in RN. Indiana Univ. Math. J. 30 (1981), 141157.CrossRefGoogle Scholar
4Brèzis, H., Peletier, L. A. and Terman, D.. A very singular solution of the heat equation with absorption. Arch. Rational Mech. Anal, (to appear).Google Scholar
5Gidas, B., Ni, W.-M. and Nirenberg, L.. Symmetry of positive solutions of nonlinear equations in RN. Adv. in Math. Suppl. Stud. 7A (1981), 369402.Google Scholar
6Jones, C. K. R. T.. Spherically symmetric waves of a reaction diffusion equation (MRC Technical Summary Report 2406, 1979).Google Scholar
7Peletier, L. A. and Serrin, J.. Uniqueness of positive solutions of semilinear equations in RN. Arch. Rational Mech. Anal. 81 (1983), 181197.CrossRefGoogle Scholar
8Peletier, L. A. and Serrin, J.. Uniqueness of nonnegative solutions of semilinear equations in RN. J. Differential Equations 61 (1986), 380397.CrossRefGoogle Scholar
9Serrin, J.. Nonlinear elliptic equations of second order. AMS Symposium in Partial Differential Equations, Berkeley, August 1971.Google Scholar
10Smoller, J. and Wasserman, A.. Global bifurcation of steady state solutions. J. Differential Equations 39 (1981), 269290.Google Scholar