deductive system
121Minimal logic — Minimal logic, or minimal calculus, is a symbolic logic system originally developed by Ingebrigt Johansson. It is a variant of intuitionistic logic that rejects not only the classical law of excluded middle (as intuitionistic logic does), but… …
122Non-classical logic — Non classical logics (and sometimes alternative logics) is the name given to formal systems which differ in a significant way from standard logical systems such as propositional and predicate logic. There are several ways in which this is done,… …
123Axiology — (from Greek ἀξίᾱ, axiā, value, worth ; and λόγος, logos) is the philosophical study of value. It is either the collective term for ethics and aesthetics[1] philosophical fields that depend crucially on notions of value or the foundation for these …
124Countable set — Countable redirects here. For the linguistic concept, see Count noun. Not to be confused with (recursively) enumerable sets. In mathematics, a countable set is a set with the same cardinality (number of elements) as some subset of the set of… …
125Empty 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… …
126Entscheidungsproblem — In mathematics, the Entscheidungsproblem (pronounced [ɛntˈʃaɪdʊŋspʁoˌbleːm], German for decision problem ) is a challenge posed by David Hilbert in 1928. The Entscheidungsproblem asks for an algorithm that will take as input a description of a… …
127Class (set theory) — In set theory and its applications throughout mathematics, a class is a collection of sets (or sometimes other mathematical objects) which can be unambiguously defined by a property that all its members share. The precise definition of class… …
128Nominalism — is a metaphysical view in philosophy according to which general or abstract terms and predicates exist, while universals or abstract objects, which are sometimes thought to correspond to these terms, do not exist.[1] Thus, there are at least two… …
