Inserting: in a formula an icon can be replaced under certain conditions by another icon. E.g. inserting a constant for a variable will make a propositional function become a sentence. See also substitutability, substitution, validity, statements, propositional functions._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. |