RT Journal Article T1 A Completeness Theorem for a Functionally Complete Łukasiewicz Logic A1 Aranda Utrero, Víctor AB We present a new axiomatization for a truth-functionally complete version of Ł3, a three-valued propositional logic, using two propositional constants and the Łukasiewicz implication as primitive symbols. We develop a corresponding proof system that incorporates Łukasiewicz’s axioms, a variant of Słupecki’s postulates for a 0-ary connective, and some properties of the Baaz delta operation. Using a weakened Deduction Theorem and adapting Henkin’s method to this three-valued setting, we establish a Completeness Theorem for the system. PB Uniwersytet Mikołaja Kopernika SN 1425-3305 YR 2026 FD 2026 LK https://hdl.handle.net/20.500.14352/123833 UL https://hdl.handle.net/20.500.14352/123833 LA eng NO Aranda, V. (2026) “A Completeness Theorem for a Functionally Complete Łukasiewicz Logic”, Logic and Logical Philosophy, pp. 1–12. doi: 10.12775/LLP.2026.010 NO Comunidad de Madrid NO Ministerio de Ciencia e Innovación (España) DS Docta Complutense RD 8 ago 2026