# name
A converse to the Schwarz lemma for planar harmonic maps

# metadata.dc.description.abstract[].value
A sharp version of a recent inequality of Kovalev and Yang on the ratio of the $(H^1)^\ast$ and $H^4$ norms for certain polynomials is obtained. The inequality is applied to establish a sharp and tractable sufficient condition for the Wirtinger derivatives at the origin for harmonic self-maps of the unit disc which fix the origin.

# metadata.dc.relation.ispartof[].value
Journal of Mathematical Analysis and Applications, 2021, vol. 497, num. 2

# metadata.dc.source[].value
Articles publicats en revistes (Matemàtiques i Informàtica)

# metadata.dc.title[].value
A converse to the Schwarz lemma for planar harmonic maps