Pm. Gauthier et D. Zwick, BEST UNIFORM APPROXIMATION BY HARMONIC-FUNCTIONS ON SUBSETS OF RIEMANNIAN-MANIFOLDS, Constructive approximation, 10(1), 1994, pp. 77-85
We investigate best uniform approximations to bounded, continuous func
tions by harmonic functions on precompact subsets of Riemannian manifo
lds. Applications to approximation on unbounded subsets of R2 are give
n.