Is a Closed Subset of a Compact Set Always Compact?

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SUMMARY

A closed subset B of a compact set A in a topological space X is always compact in X. This conclusion is based on the properties of compactness, where a subset of a compact space inherits compactness. The discussion confirms that since B is closed in X and contained within the compact set A, it retains the compactness property in the larger space X.

PREREQUISITES
  • Understanding of topological spaces
  • Familiarity with the concept of compactness in topology
  • Knowledge of closed sets in a topological context
  • Basic principles of set theory
NEXT STEPS
  • Study the properties of compact sets in topology
  • Explore examples of closed subsets in compact spaces
  • Learn about the Heine-Borel theorem and its implications
  • Investigate the relationship between open and closed sets in topology
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Mathematicians, students of topology, and anyone studying advanced concepts in set theory and compactness.

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Homework Statement


Let X be a topological space. Let A be compact in X. Let B be contained in A. Let B also be closed in X. Is it always true that B is compact in X?


Homework Equations





The Attempt at a Solution

 
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B will be compact in A, and consequently in X as well.
 

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