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| author | bnewbold <bnewbold@eta.mit.edu> | 2008-11-05 02:26:39 -0500 | 
|---|---|---|
| committer | bnewbold <bnewbold@eta.mit.edu> | 2008-11-05 02:26:39 -0500 | 
| commit | 0b113afaa8ae15d3672c6c50f6f6b5b26d78d618 (patch) | |
| tree | 5d70cff07e574ac7166535f0e71bdb4430548de5 | |
| parent | 5c146944cae9973731ae1b24f0161a1085e2c83e (diff) | |
| download | knowledge-0b113afaa8ae15d3672c6c50f6f6b5b26d78d618.tar.gz knowledge-0b113afaa8ae15d3672c6c50f6f6b5b26d78d618.zip  | |
better for now
| -rw-r--r-- | math/topology | 54 | 
1 files changed, 27 insertions, 27 deletions
diff --git a/math/topology b/math/topology index 6b44484..79beeae 100644 --- a/math/topology +++ b/math/topology @@ -17,20 +17,20 @@ subsets of :m:`$A$` fufiling the criteria:   1. The empty set and the entire set :m:`$A$`:m: are both in :m:`$\mathcal{T}$`.   2. The union of an arbitrary number of elements of :m:`$\mathcal{T}$` is  -    also in `$\mathcal{T}$`:m:. +    also in :m:`$\mathcal{T}$`. - 3. The intersection of a finite number of elements of `$\mathcal{T}$`:m: is -    also in `$\mathcal{T}$`:m:. + 3. The intersection of a finite number of elements of :m:`$\mathcal{T}$` is +    also in :m:`$\mathcal{T}$`. -If a subset `$B$`:m: of `$A$`:m: is a member of `$\mathcal{T}$`:m: then -`$B$`:m: is an open set under the topology `$\mathcal{T}$`:m:. +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. -`$\mathcal{T'}$`:m: is finer than `$\mathcal{T}$`:m: if `$\mathcal{T}$`:m: -is a subset of `$\mathcal{T'}$`:m: (and `$\mathcal{T}$`:m: is coarser);  -it is *strictly finer* if it is a proper subset (and `$\mathcal{T}$`:m: is  -*strictly coarser*). Two sets are *comprable* if either `$\mathcal{T\in T'}$`:m: -or `$\mathcal{T'\in T}$`:m:. +: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*.  @@ -41,35 +41,35 @@ Frequently Used Topologies  *Standard Topology*      The standard topology on the real line is generated by the collection of all intervals  -    `$$(a,b)=\{x|a<x<b\}$$`:m: +    :m:`$$(a,b)=\{x|a<x<b\}$$`      This is the usual definition for open sets on the real line.  *Discrete Topology* -    The topology on a set `$A$`:m: consisting of all points of `$A$`:m:; -    in other words the power set of `$A$`:m:. +    The topology on a set :m:`$A$` consisting of all points of :m:`$A$`; +    in other words the power set of :m:`$A$`.  *Trivial/Indiscrete Topology* -    The topology on a set `$A$`:m: consisting of only the empty set and `$A$`:m: -    itself. Not super interesting but it's always there (when `$A$`:m: isn't empty). +    The topology on a set :m:`$A$` consisting of only the empty set and :m:`$A$` +    itself. Not super interesting but it's always there (when :m:`$A$` isn't empty). -*Finite Complement Topology* (`$\mathcal{T_f}$`:m:) -    The topology on a set `$A$`:m: consisting of the empty set any subset  -    `$U$`:m: such that `$A-U$`:m: has a finite number of elements. +*Finite Complement Topology* (:m:`$\mathcal{T_f}$`) +    The topology on a set :m:`$A$` consisting of the empty set any subset  +    :m:`$U$` such that :m:`$A-U$` has a finite number of elements. -*Lower Limit Topology* (`$\mathbb{R}_\mathcal{l}$`:m:) +*Lower Limit Topology* (:m:`$\mathbb{R}_\mathcal{l}$`)      The lower limit topology on the real line is generated by the collection of all half open      intervals -    `$$[a,b)=\{x|a\leq x<b\}$$`:m: -    `$\mathbb{R}_\mathcal{l}$`:m: is strictly finer than the standard topology and -    is not comprable to `$\mathbb{R}_K$`:m:. +    :m:`$$[a,b)=\{x|a\leq x<b\}$$` +    :m:`$\mathbb{R}_\mathcal{l}$` is strictly finer than the standard topology and +    is not comprable to :m:`$\mathbb{R}_K$`. -*K-Topology* (`$\mathbb{R}_K$`:m:) -    Let `$K$`:m: denote the set of all numbers `$1/n$`:n: where `$n$`:m: is +*K-Topology* (:m:`$\mathbb{R}_K$`) +    Let :m:`$K$` denote the set of all numbers :m:`$1/n$` where :m:`$n$` is      a positive integer.       The K-topology on the real line is generated by the collection of all standard open intervals  -    minus `$K$`:m:.  -    `$\mathbb{R}_K$`:m: is strictly finer than the standard topology and is not -    comprable to `$\mathbb{R}_\mathcal{l}$`:m:. +    minus :m:`$K$`.  +    :m:`$\mathbb{R}_K$` is strictly finer than the standard topology and is not +    comprable to :m:`$\mathbb{R}_\mathcal{l}$`.  *Order Topology*      TODO  | 
