Łukasiewicz logic
In mathematics and philosophy, Łukasiewicz logic ( WUUK-ə-SHEV-itch, Polish: [wukaˈɕɛvitʂ]) is a non-classical, many-valued logic. It was originally defined in the early 20th century by Jan Łukasiewicz as a three-valued modal logic; it was later generalized to n-valued (for all finite integers n) as well as infinitely-many-valued (ℵ0-valued) variants, both propositional and first order.