Concave functions, Blaschke products, and polygonal mappings. Bhowmik, Bappaditya; Ponnusamy, Saminathan; Wirths, Karl-Joachim — 2009 Sibirskij Matematicheskij Zhurnal
A sharp bound for the Schwarzian derivative of concave functions Bappaditya Bhowmik; Karl-Joachim Wirths — 2012 Colloquium Mathematicae We derive a sharp bound for the modulus of the Schwarzian derivative of concave univalent functions with opening angle at infinity less than or equal to πα, α ∈ [1,2].