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The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
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- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
A space admitting a universal covering is semilocally simply connected
Statement
If a space admits a universal covering, then it is semilocally simply connected. No local path-connectedness hypothesis is required.
Facts & Assumptions
Given: The objects, hypotheses, and choice principles stated above.
A universal covering space of is a covering map whose total space is simply connected (def-covering-map-and-evenly-covered-neighbourhoods, def-simply-connected). (Universal covering spaces).
A space is semilocally simply connected at when there is a neighbourhood of and a basepoint-preserving inclusion whose induced map on fundamental groups is trivial (def-neighbourhood-top, def-induced-homomorphism-on-fundamental-groups, def-based-loops-and-fundamental-group). It is semilocally simply connected when this holds at every point. The neighbourhood need not itself be simply connected. (Semilocally simply connected spaces with explicit basepoint convention).
For a covering , the induced homomorphism is injective. (A covering map induces an injective homomorphism on fundamental groups).
A topological space is simply connected when it is nonempty and path-connected (def-path-connected) and, for every , the group has exactly one element. (Simply connected topological spaces).
Proof
At a basepoint choose an evenly covered neighbourhood and a lift of that point.
Any loop in the neighbourhood lifts to a loop in its sheet.
The induced fundamental-group map of the universal cover is injective and its domain group is trivial, so the inclusion-induced class downstairs is trivial.
No local path-connectedness is needed for this necessity direction.
The preceding construction and implications establish the assertion.
Depends on
Used by
Dependency tree · next 3 levels
Direct dependencies and their dependencies through the next three levels: 35 results over 14 levels. An arrow runs from a result to what uses it, and this result sits at the bottom with a heavier outline. Click the chart to enlarge it.
Sources
- Allen Hatcher, Algebraic Topology, §1.3 (standard reference, not scraped)
- J. Peter May, A Concise Course in Algebraic Topology, Ch. 3 (standard reference, not scraped)
- Marco Gualtieri, MAT1300 Week 4 Term 2, §1.6 (standard reference, not scraped)