Hollenbeck–Verbitsky conjecture on best constant inequalities for analytic and co-analytic projections

Lipschitz Continuity for Harmonic Functions and Solutions of the α¯-Poisson Equation

“…Many generalizations of this classical result were obtained by various mathematicians. In a broader sense, this topic is connected to the gradient estimates of spatial harmonic functions [12]. Deeper origins of this topic can also be seen in the famous Schwartz lemma, and some newer result and history of this area can be found in [3].…”