Uniqueness of boundary blow-up solutions on exterior domain of RN ✩

In this paper, we consider the existence and uniqueness of positive solutions of the degenerate logistic type elliptic equation − u = a(x)u− b(x)|u|q−1u, x ∈ RN \ D, u|∂D =∞, where N 2, D ⊂ RN is a bounded domain with smooth boundary and a(x), b(x) are continuous functions on RN with b(x) 0, b(x) ≡ 0.We show that under rather general conditions on a(x) and b(x) for large |x|, there exists a unique positive solution. Our results improve the corresponding ones in [W. Dong, Y. Du, Unbounded principal eigenfunctions and the logistic equation on RN, Bull. Austral. Math. Soc. 67 (2003) 413–427] and [Y. Du, L. Ma, Logistic type equations on RN by a squeezing method involving boundary blow-up solutions, J. London Math. Soc. (2) 64 (2001) 107–124]. © 2006 Elsevier Inc. All rights reserved