2005/12/18 by Pinchover, Yehuda · 1 citation
#35B05 #35J150 #Analysis of PDEs (math.AP) #FOS: Mathematics #Spectral Theory (math.SP)
paper · doi:10.48550/arxiv.math/0512431
In this paper we prove a sufficient condition, in terms of the behavior of a ground state of a symmetric critical operator P1, such that a nonzero subsolution of a symmetric nonnegative operator P0 is a ground state. Particularly, if Pj:=-Δ+Vj, for j=0,1, are two nonnegative Schrödinger operators defined on Ω⊆ ℝd such that P1 is critical in Ω with a ground state ϕ, the function ψ\nleq 0 is a subsolution of the equation P0u=0 in Ω and satisfies |ψ|≤ Cϕ in Ω, then P0 is critical in Ω and ψ is its ground state. In particular, ψ is (up to a multiplicative constant) the unique positive supersolution of the equation P0u=0 in Ω. Similar results hold for general symmetric operators, and also on Riemannian manifolds.