Stanisław Jaśkowski

Stanisław Jaśkowski was a Polish logician who made important contributions to proof theory and formal semantics. He was a student of Jan Łukasiewicz and a member of the Lwów–Warsaw School of Logic. He is regarded as one of the founders of natural deduction, which he discovered independently of Gerhard Gentzen in the 1930s. He is also known for his research into paraconsistent logic. He was the President (rector) of the Nicolaus Copernicus University in Toruń.