On convexity of level curves of harmonic functions in the hyperbolic plane

Papadimitrakis, M.

doi:10.1090/S0002-9939-1992-1086339-3

On convexity of level curves of harmonic functions in the hyperbolic plane
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Proc. Amer. Math. Soc. 114 (1992), 695-698 Request permission

Abstract:

We prove that if two level curves of a harmonic function are convex in the hyperbolic disc then all intermediate level curves are also convex.

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