reflexive
131Kripke semantics — (also known as relational semantics or frame semantics, and often confused with possible world semantics) is a formal semantics for non classical logic systems created in the late 1950s and early 1960s by Saul Kripke. It was first made for modal… …
132Admissible rule — In logic, a rule of inference is admissible in a formal system if the set of theorems of the system is closed under the rule. The concept of an admissible rule was introduced by Paul Lorenzen (1955).DefinitionsThe concept of admissibility, as… …
