Partiality and its dual
This paper is worth reading. A number of fundamental logical systems are under consideration, here in their semantical interconnection. The semantical approach explores allowing truth-value assignments to be undetermined or ``partial'' (no truth values) and overdetermined or ``inconsistent'' (both truth values), thus returning to an investigation of the four-valued semantics that was initiated by the author in the sixties.
scientific article; zbMATH DE number 1563234