Periodic curve as immersed submanifold

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Discussion Overview

The discussion revolves around whether a periodic curve can be considered an immersed submanifold of a manifold M. Participants explore the implications of periodicity on the injectivity of the curve and the conditions necessary for it to qualify as an immersed submanifold.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions if a periodic curve, which is not injective, can still be an immersed submanifold, given that an immersed submanifold must be the image of an injective immersion.
  • Another participant suggests that instead of an interval, one might consider immersing S^1 to account for the periodic nature of the curve.
  • A clarification is made regarding the necessity of the condition y'(t) ≠ 0 for all t to assert that y is an immersion, implying that without this condition, the image of the curve may not be an immersed submanifold.
  • It is proposed that even if y is not injective, its image could still be an immersed submanifold of M, as a periodic map from R to M can be represented as a map from S^1 to M, covering a single period when traversing the circle.
  • Additionally, if y is injective during each period, then the resulting map Y is an injective immersion.

Areas of Agreement / Disagreement

Participants express differing views on the implications of periodicity and injectivity for the classification of the curve as an immersed submanifold. The discussion remains unresolved regarding the conditions under which a periodic curve can be considered an immersed submanifold.

Contextual Notes

Participants highlight the importance of the derivative condition y'(t) ≠ 0 and the implications of mapping from R to S^1, indicating that the discussion is contingent on these mathematical definitions and conditions.

robforsub
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Is a periodic curve still an immersed submanifold of a manifold M? Suppose y is the curve
map an interval to a manifold M, and y is periodic, which means it is not injective. And immersed submanifold must be the image of a injective immersion.
 
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If it's periodic, maybe you want to immerse S^1 instead of an interval.
 
Let me clarify it a little bit, so I want to show that the image of that curve y is a immersed submanifold of manifold M, and without the condition y'(t)!=0 for all t, I can not say y is a immersion, then the image of curve y is immersed submanifold, right?
 
What I mean is that, if y' is everywhere nonzero, then y is an immersion. And although y isn't injective, its image may still be an immersed submanifold of M, since a periodic map from R to M descends to a map Y from S^1 to M, so that going once around the circle covers a single period. And if y is injective during each period, then Y is an injective immersion.
 

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