free ultrafilter

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• Ultrafilter — In the mathematical field of set theory, an ultrafilter on a set X is a collection of subsets of X that is a filter, that cannot be enlarged (as a filter). An ultrafilter may be considered as a finitely additive measure. Then every subset of X is …   Wikipedia

• Hyperreal number — *R redirects here. For R*, see Rockstar Games. The system of hyperreal numbers represents a rigorous method of treating the infinite and infinitesimal quantities. The hyperreals, or nonstandard reals, *R, are an extension of the real numbers R… …   Wikipedia

• Connes embedding problem — In von Neumann algebras, the Connes embedding problem or conjecture, due to Alain Connes, asks whether every type II1 factor on a separable Hilbert space can be embedded into the ultrapower of the hyperfinite type II1 factor by a free ultrafilter …   Wikipedia

• List of forcing notions — In mathematics, forcing is a method of constructing new models M[G] of set theory by adding a generic subset G of a poset P to a model M. The poset P used will determine what statements hold in the new universe (the extension ); to force a… …   Wikipedia

• Boolean algebras canonically defined — Boolean algebras have been formally defined variously as a kind of lattice and as a kind of ring. This article presents them more neutrally but equally formally as simply the models of the equational theory of two values, and observes the… …   Wikipedia

• Boolean-valued model — In mathematical logic, a Boolean valued model is a generalization of the ordinary Tarskian notion of structure or model, in which the truth values of propositions are not limited to true and false , but take values in some fixed complete Boolean… …   Wikipedia

• Filter (mathematics) — The powerset algebra of the set {1,2,3,4} with the upset colored green. The green elements make a principal ultrafilter on the lattice. In mathematics, a filter is a special subset of a partially ordered set. A frequently used special case is the …   Wikipedia

• Stone–Čech compactification — In the mathematical discipline of general topology, Stone–Čech compactification is a technique for constructing a universal map from a topological space X to a compact Hausdorff space beta; X . The Stone–Čech compactification beta; X of a… …   Wikipedia

• List of order theory topics — Order theory is a branch of mathematics that studies various kinds of binary relations that capture the intuitive notion of ordering, providing a framework for saying when one thing is less than or precedes another. An alphabetical list of many… …   Wikipedia

• PCF theory — is the name of a mathematical theory, introduced by Saharon Shelah (1978), that deals with the cofinality of the ultraproducts of ordered sets. It gives strong upper bounds on the cardinalities of power sets of singular cardinals, and has… …   Wikipedia

• Forcing (mathematics) — For the use of forcing in recursion theory, see Forcing (recursion theory). In the mathematical discipline of set theory, forcing is a technique invented by Paul Cohen for proving consistency and independence results. It was first used, in 1963,… …   Wikipedia