Lifting of a continuous map through a covering map
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[hide]Definition
Let (X,J) be a topological space, let (E,H) be a covering space of X, with covering map p:E→X. Then[1][2]:
- if we're given a continuous map f:Y→X for an arbitrary topological space (Y,K) such that:
- there exists a continuous map, φ:Y→E, such that p∘φ=f (the diagram on the right commutes)
- then φ is called a lifting of f (through p)
- there exists a continuous map, φ:Y→E, such that p∘φ=f (the diagram on the right commutes)
Caveat:I am not sure if we require Y be a connected topological space or not[Note 1] - however if we do then the unique lifting property applies.
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Notes
- Jump up ↑ Author notes for future use:
- Lee requires that the disjoint elements of an even covering which are homeomorphic to the open neighbourhood be themselves connected topological (sub)spaces
- Lee then requires the covering space be connected and locally path-connected
- He does not require Y to be connected. But for the unique lifting property he does require Y to be connected
- Gamelin and Greene do not require anything be connected until they reach lifts (here) where Y must be connected.
- Lee requires that the disjoint elements of an even covering which are homeomorphic to the open neighbourhood be themselves connected topological (sub)spaces