The Craig-Lyndon interpolation theorem in 3-valued logic
Robin Gill · Journal of Symbolic Logic · 1970
The purpose of this paper is to provide a formal system which is (a) adequate (functionally complete), (b) consistent, and (c) complete, relative to 3-valued logic with one designated value, and for which, furthermore, (d) a simple normal form theorem, and (e) the Craig-Lyndon Interpolation Theorem [1], [2] holds.