From f61026119df4700f69eb73e95620bc5928ca0fcb Mon Sep 17 00:00:00 2001 From: User Date: Tue, 13 Oct 2009 02:52:09 +0000 Subject: Grand rename for gitit transfer --- math/topology | 81 ----------------------------------------------------------- 1 file changed, 81 deletions(-) delete mode 100644 math/topology (limited to 'math/topology') diff --git a/math/topology b/math/topology deleted file mode 100644 index 6f03eee..0000000 --- a/math/topology +++ /dev/null @@ -1,81 +0,0 @@ -==================== -Topology -==================== - -.. warning:: Incomplete; in progress - -.. note:: Most of the definitions and notation in the section are based on [munkres]_ - -A *topological space* is a set for which a valid topology has been defined: the topology -determines which subsets of the topological space are open and closed. In this way the -concept of open and closed subsets on the real number line (such as :m:`$(0,1)$` and -:m:`$[1,2]$`) are generalized to arbitrary sets. - -Formally, a *topology* on a set :m:`$A$` is a collection :m:`$\mathcal{T}$` of -subsets of :m:`$A$` fufiling the criteria: - - 1. The empty set and the entire set :m:`$A$` are both in :m:`$\mathcal{T}$`. - - 2. The union of an arbitrary number of elements of :m:`$\mathcal{T}$` is - also in :m:`$\mathcal{T}$`. - - 3. The intersection of a finite number of elements of :m:`$\mathcal{T}$` is - also in :m:`$\mathcal{T}$`. - -If a subset :m:`$B$` of :m:`$A$` is a member of :m:`$\mathcal{T}$` then -:m:`$B$` is an open set under the topology :m:`$\mathcal{T}$`. - -*Coarseness* and *Fineness* are ways of comparing two topologies on the same space. -:m:`$\mathcal{T'}$` is finer than :m:`$\mathcal{T}$` if :m:`$\mathcal{T}$` -is a subset of :m:`$\mathcal{T'}$` (and :m:`$\mathcal{T}$` is coarser); -it is *strictly finer* if it is a proper subset (and :m:`$\mathcal{T}$` is -*strictly coarser*). Two sets are *comprable* if either :m:`$\mathcal{T\in T'}$` -or :m:`$\mathcal{T'\in T}$`. -*Smaller* and *larger* are somtimes used instead of finer and coarser. - -Topologies can be generated from a *basis*. - -TODO: Hausdorf - -Frequently Used Topologies -============================ - -*Standard Topology* - The standard topology on the real line is generated by the collection of all intervals - :m:`$$(a,b)=\{x|a