Handles and non-orientible 3D manifolds

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    3d Manifolds
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SUMMARY

This discussion focuses on the construction of 3D manifolds using handles, specifically defining a "3-handle" as a 3-sphere x interval product. The process involves cutting out two balls from an S3 and attaching the ends to create a 3-donut or a solid Klein bottle by gluing one end incorrectly. The conversation also explores the use of crosscaps and crossballs to form non-orientable manifolds like the real projective space. Additionally, the participants seek to establish rules for combining handles in 3D, referencing surgery theory and connected sums as foundational concepts.

PREREQUISITES
  • Understanding of 2D manifolds and their properties, including handles and crosscaps.
  • Familiarity with 3D manifolds and the concept of S3 (3-sphere).
  • Knowledge of surgery theory and its application in topology.
  • Basic comprehension of orientable and non-orientable surfaces.
NEXT STEPS
  • Research "surgery theory" to understand its role in higher-dimensional topology.
  • Explore the concept of "connected sums" and its implications for manifold construction.
  • Investigate the properties and applications of crosscaps in 3D manifolds.
  • Study the classification of 3D manifolds and the rules for combining different types of handles.
USEFUL FOR

Mathematicians, topologists, and students interested in manifold theory, particularly those exploring the construction and classification of 3D manifolds using handles.

bsaucer
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I've read that with 2D manifolds, you can create any closed 2D manifold by adding "handles" or "crosscaps" (or "crosshandles"). To add a handle, cut out two disks and add the ends of a circle x interval product (cylinder). If you glue one end "the wrong way" you get a "crosshandle", which is how you get a Klein bottle. A "crosscap" is equivalent to a Mobius strip, but it has a circular boundary (instead of a figure-8 boundary folded up double). Use a crosscap to create a projective plane.

There are some "rules" that apply for 2D surfaces: a handle in the presence of a crosscap can be converted to a crosshandle. Two crosscaps can be combined into a crosshandle.

I'm trying to come up with a set of rules for creating 3D manifolds using "handles". If I define a "3-handle" as a 3-sphere x interval product, I can cut out two balls from an S3 and add the two ends of the handle to produce a 3-donut. Or I can glue one end the "wrong way" (adding a 3-crosshandle) and get a "solid Klein bottle".

I can also cut out a ball and plug in a "crossball" to get a real projective space.

You can cut out a solid torus (disk x circle product) and glue it back in a twisted way. Or you can glue in crosscap x circle product (which has a torus boundary). I'm not sure what you'd get.

Are there any other types of "handles" you can attach? I want to cover both orientable and non-orientable cases. Are there any rules about combining these in 3D?
 
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The generalization of attaching handles to higher dimensions is called "http://en.wikipedia.org/wiki/Surgery_theory" ". The operation you are describing is a special case.
I also suggest you look at the article on the http://en.wikipedia.org/wiki/Connected_sum" .
 
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