ordinal
111Successor ordinal — When defining the ordinal numbers, an absolutely fundamental operation that we can perform on them is a successor operation S to get the next higher one. Using von Neumann s ordinal numbers (the standard ordinals used in set theory), we have, for …
112Church–Kleene ordinal — In mathematics, the Church–Kleene ordinal, , is a large countable ordinal. It is the smallest non recursive ordinal. It is named after Alonzo Church and S. C. Kleene. References Church, Alonzo; Kleene, S. C. (1937), Formal definitions in the… …
113Bachmann–Howard ordinal — In mathematics, the Bachmann–Howard ordinal (or Howard ordinal) is a large countable ordinal.It is the proof theoretic ordinal of several mathematical theories, such as Kripke–Platek set theory (with the axiom of infinity) and the system CZF of… …
114Admissible ordinal — In set theory, an admissible ordinal is any ordinal number α such that Lα is a standard set model of Kripke–Platek set theory. In this case, Lα is said to be an admissible set.The first two admissible ordinals are ω and omega 1^{mathrm{CK (the… …
115Small Veblen ordinal — In mathematics, the small Veblen ordinal is a certain large countable ordinal, named after Oswald Veblen. It is occasionally called the Ackermann ordinal, though the Ackermann ordinal described by harvtxt|Ackermann|1951 is somewhat smaller than… …
116Feferman–Schütte ordinal — In mathematics, the Feferman–Schütte ordinal Gamma;0 is a large countable ordinal.It is the proof theoretic ordinal of several mathematical theories.It is named after Solomon Feferman and Kurt Schütte.It is sometimes said to be the first… …
117Ackermann ordinal — In mathematics, the Ackermann ordinal is a certain large countable ordinal, named after Wilhelm Ackermann. The term Ackermann ordinal is also occasionally used for the small Veblen ordinal, a somewhat larger ordinal. Unfortunately there is no… …
118Recursive ordinal — In mathematics, specifically set theory, an ordinal α is said to be recursive if there is a recursive binary relation R that well orders a subset of the natural numbers and the order type of that ordering is α. It is trivial to check that ω is… …
119Indicateur ordinal — Dans les langues écrites, un indicateur ordinal est un signe adjacent à un nombre indiquant le fait que c est un nombre ordinal plutôt qu un nombre cardinal. La typographie utilisée varie en fonction des langues. Sommaire 1 Utilisation 1.1… …
120Premier ordinal non dénombrable — Cet article court présente un sujet plus développé dans : Ordinal de Hartogs. Le premier ordinal non dénombrable, noté ω1 ou parfois Ω, est le plus petit ordinal non dénombrable (par conséquent c est un ordinal initial) ; c est aussi l… …
