dense subset

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• Dense set — In topology and related areas of mathematics, a subset A of a topological space X is called dense (in X) if any point x in X belongs to A or is a limit point of A.[1] Informally, for every point in X, the point is either in A or arbitrarily close …   Wikipedia

• Dense submodule — In abstract algebra, specifically in module theory, a dense submodule of a module is a refinement of the notion of an essential submodule. If N is a dense submodule of M, it may also be said it may alternatively be said that N ⊆ M is a… …   Wikipedia

• Dense-in-itself — In mathematics, a subset A of a topological space is said to be dense in itself if A contains no isolated points. Every dense in itself closed set is perfect. Conversely, every perfect set is dense in itself. A simple example of a set which is… …   Wikipedia

• dense — densely, adv. denseness, n. /dens/, adj., denser, densest. 1. having the component parts closely compacted together; crowded or compact: a dense forest; dense population. 2. stupid; slow witted; dull. 3. intense; extreme: dense ignorance. 4.… …   Universalium

• Nowhere dense set — A subset A of a topological space X is nowhere dense in X if and only if the interior of the closure of A is empty. The order of operations is important. For example, the set of rational numbers, as a subset of R has the property that the closure …   Wikipedia

• Glossary of topology — This is a glossary of some terms used in the branch of mathematics known as topology. Although there is no absolute distinction between different areas of topology, the focus here is on general topology. The following definitions are also… …   Wikipedia

• Meagre set — In the mathematical fields of general topology and descriptive set theory, a meagre set (also called a meager set or a set of first category) is a set that, considered as a subset of a (usually larger) topological space, is in a precise sense… …   Wikipedia

• Separable space — In mathematics a topological space is called separable if it contains a countable dense subset; that is, there exists a sequence { x n } {n=1}^{infty} of elements of the space such that every nonempty open subset of the space contains at least… …   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

• Generic property — In mathematics, properties that hold for typical examples are called generic properties. For instance, a generic property of a class of functions is one that is true of almost all of those functions, as in the statements, A generic polynomial… …   Wikipedia

• Uniform space — In the mathematical field of topology, a uniform space is a set with a uniform structure. Uniform spaces are topological spaces with additional structure which is used to define uniform properties such as completeness, uniform continuity and… …   Wikipedia