Topological indistinguishability: Difference between revisions

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==Definition==
==Definition==


'''Topological induistinguishability''' is an equivalence relation on any [[topological space]]. For a topological space <math>X</math>, two (possibly equal, possibly distinct) points <math>x,y \in X</math> are termed '''topologically indinstinguishable''' if the following equivalent conditions hold:
'''Topological indistinguishability''' is an equivalence relation on any [[topological space]]. For a topological space <math>X</math>, two (possibly equal, possibly distinct) points <math>x,y \in X</math> are termed '''topologically indinstinguishable''' if the following equivalent conditions hold:


# The [[closure]]s of the singleton sets <math>\{ x \}</math> and <math>\{ y \}</math> are equal.
# The [[closure]]s of the singleton sets <math>\{ x \}</math> and <math>\{ y \}</math> are equal.

Latest revision as of 02:14, 28 January 2012

Definition

Topological indistinguishability is an equivalence relation on any topological space. For a topological space X, two (possibly equal, possibly distinct) points x,yX are termed topologically indinstinguishable if the following equivalent conditions hold:

  1. The closures of the singleton sets {x} and {y} are equal.
  2. Every closed subset containing x contains y and every closed subset containing y contains x.
  3. Every open subset containing x contains y and every open subset containing y contains x.

Two distinct points that are not topologically indistinguishable are termed topologically distinguishable.

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