Václav Jaroslav Karel Pinkava (Czech pronunciation: [ˈvaːtslaf ˈjaroslaf ˈkarɛl ˈpɪŋkava]; 9 December 1926 – 13 August 1995), better known by his pen name Jan Křesadlo (pronounced [ˈjan ˈkr̝ɛsadlo]), was a Czech psychologist who was also a prizewinning novelist and poet. Pinkava was also active in choral music, composing (among others) a Glagolitic Mass. As well, he worked in mathematical logic, discovering the many-valued logic algebra which bears his name. He is the father of film director Jan Pinkava who received an Oscar for Geri's Game in 1998 and also illustrated GraveLarks.