Electronic Journal of Differential Equations, Vol. 2002(2002), No. 101, pp. 1-22. Title: On the properties of infinity-harmonic functions and an application to capacitary convex rings Author: Tilak Bhattacharya (Bishop's Univ., Lennoxville, Canada) Abstract: We study positive $\infty$-harmonic functions in bounded domains. We use the theory of viscosity solutions in this work. We prove a boundary Harnack inequality and a comparison result for such functions near a flat portion of the boundary where they vanish. We also study $\infty$-capacitary functions on convex rings. We show that the gradient satisfies a global maximum principle, it is nonvanishing outside a set of measure zero and the level sets are star-shaped. Submitted August 17, 2002. Published November 28, 2002. Math Subject Classifications: 35J70, 26A16. Key Words: Viscosity solutions; boundary Harnack inequality; infinity-Laplacian; capacitary functions; convex rings