Consequences of a Codimension One and One-Dimensional Foliations on Topology

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Discussion Overview

The discussion centers around the implications of codimension one and one-dimensional foliations on the topology of spaces. Participants explore the relationship between foliation theory and topology, particularly in the context of the Euler characteristic and its consequences for manifold structures.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes a theorem stating that a codimension one foliation exists if and only if the Euler characteristic of the topological space is one, prompting inquiry into the implications of having both codimension one and one-dimensional foliations simultaneously.
  • Another participant questions the clarity of the initial inquiry and suggests exploring the properties of smooth curves in R^3 and their differentiable mappings to R^1, raising issues of continuity.
  • A different participant introduces a counterexample by mentioning a compact manifold without boundary whose Cartesian product with a circle has a codimension one foliation but an Euler characteristic of zero, suggesting a potential conflict with the initial theorem.
  • Another participant references the relationship between k-plane bundles and their Euler classes, indicating a connection to the discussion of foliations and topology.

Areas of Agreement / Disagreement

Participants express differing views on the implications of foliations and the Euler characteristic, with some providing examples that challenge the initial premise. The discussion remains unresolved with multiple competing perspectives on the topic.

Contextual Notes

The discussion highlights limitations in the assumptions regarding the relationship between foliations and Euler characteristics, as well as the specific conditions under which these properties hold. The implications of differentiability and continuity in the context of foliations are also not fully resolved.

center o bass
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I was suprised to realize that foliation theory was actually closely related to topology. Indeed, http://www.map.mpim-bonn.mpg.de/Foliations, states a theorem which say that a codimension one foliation exists if and only if the Euler characteristic of the topological space is one!

I am currently working with foliations, so I wondered if someone here knew the consequences of both a codimesion one foliation _and_ a one-dimensional foliation existing on the same time?

What does it imply for the topology?

The first type of foliation is often known as hypersurface foliations (or slicing), while the second is known also known as threading.
 
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I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?
 
your question is a little vague, but here goes. what are the open sets of a smooth curve in R^3 (for example)? then what is a differentiable map from this curve into R^1? what does differentiability imply about continuity?
 
Take any compact manifold without boundary and take its Cartesian product with a circle. The product has a codimension 1 foliation but it's Euler characteristic is zero.
 
Last edited:
From what I remember, if you have a k-plane bundle of fiber F ## M \rightarrow B ## , its Euler class is ## \chi (F) PD(M) ## , where ## \chi ## is the Euler characteristic and PD is the Poincare dual.
 

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