Question about covering map of punctured unit disk

In summary, the discussion revolves around the properties of covering maps in relation to the punctured unit disk. It addresses how such maps can be constructed, the implications of puncturing on the topology of the disk, and the behavior of paths and loops within this space. The focus is on understanding the fundamental group of the punctured disk and how it influences the covering space's characteristics.
  • #1
MathLearner123
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Let ##\alpha \in \mathbb{R}^*,\, p:\mathbb{H} \to \mathbb{D} \setminus \{0\}, \, p(z) = e^\frac{2 \pi i z}{|a|}##. I want to show that ##p## is a covering map but I dont't know how to make this. I think I need to start with an ##y \in \mathbb{D} \setminus \{0\}## and take an open disk ##D \subset \mathbb{D} \setminus \{0\}## to be a neighbourhood of ##y##. Now, because disk is open and connected, there exists a holomorphic branch of logarithm in ##D##. It's ok this start? How I can continue? Thanks!
 
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  • #2
Sorry for my ignorance -- What is ##\mathbb{R}^*##? Is ##\mathbb{H}## a half-plane?
 
  • #3
@FactChecker ##\mathbb{R}^* = \mathbb{R} \setminus \{0\}## and ##\mathbb{H}## is the upper half-plane
 
  • #4
I think you may need to include more at the branch cut. I think that ##\mathbb{H}## does not include any of the real line. Don't you need to include the real line in the domain of ##p## in addition to ##\mathbb{H}## in order to cover ##\mathbb{D} \setminus \{0\}##? And doesn't the domain need to include an open set that includes the reals?

CORRECTION: My mistake. The positive reals in ##\mathbb{D} \setminus \{0\}## will be covered by the image of ##z=x+|\alpha|i##.
 
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