Continuity between topological spaces
Continuity preserves openness through inverse images.
Key knowledge
A map f:X→Y between topological spaces is continuous exactly when f⁻¹(U) is open in X for every open subset U of Y.
Conditions and scope
- Both topologies must be declared.
- Inverse image does not require f to have an inverse function.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Section 1.1: topology axioms and inverse-image continuity; printed page 11, physical page 9.
2026-10-10 · Topological continuity definition only.
Entry details
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- math-continuity-topology
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- university-reference.1
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- University reference