primitive recursive term
81Metamathematics — is the study of mathematics itself using mathematical methods. This study produces metatheories, which are mathematical theories about other mathematical theories. Metamathematical metatheorems about mathematics itself were originally… …
82Löwenheim–Skolem theorem — In mathematical logic, the Löwenheim–Skolem theorem, named for Leopold Löwenheim and Thoralf Skolem, states that if a countable first order theory has an infinite model, then for every infinite cardinal number κ it has a model of size κ. The… …
83Paraconsistent logic — A paraconsistent logic is a logical system that attempts to deal with contradictions in a discriminating way. Alternatively, paraconsistent logic is the subfield of logic that is concerned with studying and developing paraconsistent (or… …
84Rigour — For the medical term, see Rigor (medicine). For the sign of death, see Rigor mortis. Rigour or rigor (see spelling differences) has a number of meanings in relation to intellectual life and discourse. These are separate from public and political… …
85Decidability (logic) — In logic, the term decidable refers to the decision problem, the question of the existence of an effective method for determining membership in a set of formulas. Logical systems such as propositional logic are decidable if membership in their… …
86Deontic logic — is the field of logic that is concerned with obligation, permission, and related concepts. Alternatively, a deontic logic is a formal system that attempts to capture the essential logical features of these concepts. Typically, a deontic logic… …
87Argument — This article is about the subject as it is studied in logic and philosophy. For other uses, see Argument (disambiguation). In philosophy and logic, an argument is an attempt to persuade someone of something, by giving reasons or evidence for… …
88Logical truth — is one of the most fundamental concepts in logic, and there are different theories on its nature. A logical truth is a statement which is true and remains true under all reinterpretations of its components other than its logical constants. It is… …
89Diagonal lemma — In mathematical logic, the diagonal lemma or fixed point theorem establishes the existence of self referential sentences in certain formal theories of the natural numbers specifically those theories that are strong enough to represent all… …
90Empty set — ∅ redirects here. For similar looking symbols, see Ø (disambiguation). The empty set is the set containing no elements. In mathematics, and more specifically set theory, the empty set is the unique set having no elements; its size or cardinality… …
