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Movies of some neat cubical complexes.

I made some movies of some of my favorite complexes: let I^n be the n-dimensional cube, and let e_1, \ldots, e_n be the n edges around the origin, and let e_i e_j be the square face containing the edges e_i and e_j. Define a subcomplex \Sigma^2_n \subset I^n consisting of the squares e_1 e_2, e_2 e_3, \ldots, e_{n-1} e_n, e_n e_1 and all the squares in I^n parallel to these. It turns out that \Sigma^2_n is a surface with a lot of symmetries.

In particular \Sigma^2_4 is a torus in \R^4, and here is a quicktime movie of it spinning:

I’m particularly fond of this, as you can really see that four squares are coming together at each vertex (hence, it has zero curvature), and you can see the hole in the torus as it spins.

The complex \Sigma^2_5 is a genus five surface in \R^5, and here is a quicktime movie of it spinning:

I represented the extra dimensions with color—not that it helps much!

Comments

Comment from Carlos
Time: November 4, 2008, 10:35 am

These are indeed very neat!

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