PageHeader : Funkcialaj Ekvacioj, 20 (1976) 97-114 Title : On Differentiability of the Minimal Time Function AuthorInfo : By AuthorInfo : Otomar HAJEK* AuthorInfo : (Case Western Reserve University, U.S.A.) section : 1. Introduction, notation, summary. section : 2. Basic apparatus. section : 3. Local behavior. section : 4. Maximality principles. section : 5. Some consequences. section : References