I Describing 3d Manifold Objects as a Hypersurface

  • I
  • Thread starter Thread starter decentMO
  • Start date Start date
  • Tags Tags
    3d Manifold
decentMO
Messages
2
Reaction score
0
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?
 
Physics news on Phys.org
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!
 
A sphere as topological manifold can be defined by gluing together the boundary of two disk. Basically one starts assigning each disk the subspace topology from ##\mathbb R^2## and then taking the quotient topology obtained by gluing their boundaries. Starting from the above definition of 2-sphere as topological manifold, shows that it is homeomorphic to the "embedded" sphere understood as subset of ##\mathbb R^3## in the subspace topology.
Back
Top