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1. The original article: http://theconversation.com/after-400-years-mathematicians-find-a-new-class-of-solid-shapes-23217 http://theconversation.com/after-400-y
by dalek_cannes 13y ago
1. The original article: http://theconversation.com/after-400-years-mathematicians-find-a-new-class-of-solid-shapes-23217 http://theconversation.com/after-400-years-mathematicians-fi...
2. It actually looks more like a redefinition than a new discovery: "It may be confusing because Goldberg called them polyhedra, a perfectly sensible name to a graph theorist, but to a geometer, polyhedra require planar faces "
- Codhisattva 13y agoIndeed. A better title may be "After 400 years, a debate over a definition begins among mathematicians."
- JoeAltmaier 13y agoI don't think that's quite right. They narrowed the definition to strict polyhedral, which hadn't been done before. Then showed that they existed. "Schein and his colleague James Gayed have described that a fourth class of convex polyhedra, which given Goldberg’s influence they want to call Goldberg polyhedra, even at the cost of confusing others. "
- JoeAltmaier 13y agoHey! There are in fact infinite solution. Each regular face of an icosahedron for instance can be 'inflated' to form a slight dome, made out of smaller regular polygons. Then, recurse!
- jjoonathan 13y ago> convex
- JoeAltmaier 13y agoEach surface polygon is flat. They can be 'inflated' via the OPs technique without violating the bound of an enclosing sphere, right? Each recursive expansion has an inflation factor that scales. Hm. But the sphereical section bounding each polygon doesn't scale, it becomes 'flatter' as you recurse. So there's a limit.
- ehartsuyker 13y agoActually, not. The definition of convex is that given a point A and a point B and a line between A and B, all points on the line AB are in the interior space of the solid. Inflating two adjacent surfaces creates a valley along the pre-existing edge between the two of them and fails the above definition.
- JoeAltmaier 13y agoYet that's what the OP describe. Remember, the edge was a "mountain" to begin with, you have some wiggle room. That's the observation that the whole paper is based upon.
- lotharbot 13y agoGoldberg polyhedra: http://en.wikipedia.org/wiki/Goldberg_polyhedron http://en.wikipedia.org/wiki/Goldberg_polyhedron As far as I can tell, the discovery here (if there is one at all) is a method for constructing those polyhedra and others like them and being sure they're actually polyhedral (no curved or bent faces).