Describing 3d Manifold Objects as a Hypersurface

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Discussion Overview

The discussion revolves around the characterization of closed (regular) manifolds in 3D Euclidean space and whether they can be uniquely described by specific parameters, including volume, centroid, and second moments of area. Participants explore the implications of these parameters in relation to the concept of hypersurfaces and their dimensionality, as well as the distinction between topology and differential geometry.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant proposes that any closed manifold in 3D can be described by volume, centroid, and second moments of area, suggesting a unique characterization.
  • Another participant notes that a hypersurface has codimension 1, indicating it exists in a dimension one higher than the surface itself.
  • There is a suggestion that the space parametrizing all solids in 3D may be realized as an 11-dimensional manifold in 12-dimensional space, framing this as a question in differential geometry rather than topology.
  • A participant expresses a desire to understand the differences between topology and differential geometry and seeks reading recommendations for further study.

Areas of Agreement / Disagreement

Participants express varying interpretations of the original question, with some clarifying the distinction between topology and differential geometry. The discussion remains unresolved regarding the characterization of manifolds and the dimensionality of the space they occupy.

Contextual Notes

The discussion involves assumptions about the definitions of manifolds and hypersurfaces, as well as the mathematical framework required to explore these concepts. There are unresolved aspects regarding the implications of the proposed parameters and their relationship to the dimensionality of the manifold space.

decentMO
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Hello, an engineer here that is trying to understand more in topology for some mechanics ideas. It seems to me that any closed (regular) manifold in 3d Euclidean space should be able to be describe uniquely by the combination of the following 1) volume [1 real], 2) centroid [3 reals], and 3) second moments of area [9 reals cast to 7 since third axis is orthogonal to cross of 1st and 2nd]. The surface is defined of the object as C0 or higher. Can anyone give any direction as to confirming this conjecture? Is there an 11-dimensional hypersurface that is known that defines the permissible (manifold) objects in R3?
 
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decentMO said:
Hello, an engineer here that is trying to understand more in topology for some mechanics ideas. It seems to me that any closed (regular) manifold in 3d Euclidean space should be able to be describe uniquely by the combination of the following 1) volume [1 real], 2) centroid [3 reals], and 3) second moments of area [9 reals cast to 7 since third axis is orthogonal to cross of 1st and 2nd]. The surface is defined of the object as C0 or higher. Can anyone give any direction as to confirming this conjecture? Is there an 11-dimensional hypersurface that is known that defines the permissible (manifold) objects in R3?
In the standard setup you can only embed ##n-## manifolds in ##n-## dimensional space or lower. By the same setup , a hypersuface has codimension 1 , i.e., lives in dimension of the surface+1.
 
i think he is asking whether the space parametrizing all solids? in 3 space can itself be realized as an 11 dimensional manifold in I guess 12 space. This is of course not a topological question since he is using volume and area, but a question in differential geometry.
 
mathwonk said:
i think he is asking whether the space parametrizing all solids? in 3 space can itself be realized as an 11 dimensional manifold in I guess 12 space. This is of course not a topological question since he is using volume and area, but a question in differential geometry.

Yes, that's it. Thank you for clarifying for me and my apologies as I am not familiar with the differences between topology and differential geometry. Would it be helpful to move this question to a different forum? I'm want to do some reading on this subject but I'm not sure where to start in the right direction, so if you have salient reading recommendations, I'm open to suggestions. Thanks!
 

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