Last edited 21dec97 by George Francis

Homotopies

Here are three eversions from the rtica ``five'' followed by some new eversions, and finally a real treat: illiNarnia. This new project is based on Ken Brakke's Polycut and deals with branched coverings. The first one.mpg everts a cylinder. It is based on Bernard Morin's 1977 formulas.
The next two are sphere eversions made by Francois Apery and Chris Hartman in the summer of 1992. The cuboctahedral eversion is a piecewise linear version of the gastrulate eversion.

An admittedly still poor mpeg movie of the minimax sphere eversion is fresh out of the film can. If you have trouble viewing it, please let us know. It was encoded with mpeg_encode, and we know that mpeg_play does not do a good job decoding it. But most other mpeg decoders work just fine.

There will be more here on these and other homotopies here soon. And, hopefully, better mpegs.

Here are two eversions of the sphere that will be part of the Optiverse (stay tuned).

Trivert takes a double cover of Boy's surface to a sphere down the minimax Willmore energy gradient, while Bivert is a remake of earlier eversion. It takes Morin's surface down the minimax Willmore energy gradient.