Lewis, John L.2018-08-212018-08-211994-07-06Lewis, J. L. (1994). On critical points of p harmonic functions in the plane. <i>Electronic Journal of Differential Equations, 1994</i>(03), pp. 1-4.1072-6691https://hdl.handle.net/10877/7560We show that if u is a p harmonic function, 1 < p < ∞, in the unit disk and equal to a polynomial P of positive degree on the boundary of this disk, then ∇u has at most deg P − 1 zeros in the unit disk.Text4 pages1 file (.pdf)enAttribution 4.0 Internationalp-harmonic functionsp-LaplacianQuasiregular mappingsArticle