Connectedness is connected union-closed: Difference between revisions

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Revision as of 18:05, 26 January 2012

Statement

Version using a pivoting set

Suppose X is a topological space. Suppose A is a subset of X and Bi,i∈I is a collection of subsets of X. Suppose that:

  1. A is a connected space in the subspace topology.
  2. For each i∈I, Bi is a connected space in the subspace topology.
  3. A∩Bi is non-empty for each i∈I>

Then, the space:

A∪⋃i∈IBi

is a connected space in the subspace topology from X.

Version using finite hopping

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