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professor emeritus

Reged: 05/16/11

Loc: Bangalore, India
Re: Beautiful, intriguing, elegant ideas new [Re: Otto Piechowski]
      #5617106 - 01/11/13 11:38 AM


I am curious, is the pythagorean theorem or some version of it applicable to spherical trig (triangles on the surfaces of spheres and other shapes)?

For a right angle triangle composed of geodetics on a sphere with radius R, the Pythagorean theorem takes a very elegant form:
cos(c/R) = cos(a/R).cos(b/R).

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Reged: 10/05/08

Loc: Palo alto, CA.
Re: Beautiful, intriguing, elegant ideas new [Re: JKoelman]
      #5619956 - 01/12/13 10:46 PM


If a Möbius strip is going to be included, shouldn't a Klein bottle be too?

'Topology' is about mapping one shape onto another(and hopefully back), same applies to the triangle onto sphere, any shape onto another, there's more than one way around the barn though I think the branches (algebraic or point set) are converging (if not considered already so). Relatively simple questions like this can be astonishingly difficult to prove - as was the recently solved Poincare Conjecture. It's important to consider exactly which space(flat, curved, other) you are mapping to and from and backwards upside down. It's in many ways important to consider if asking for all potential sizes or small from one to another. Small triangle onto large Klein bottle, Moebius stip, sphere... or large onto small... helps if creating a Klein bottle 'opener'

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Humble Megalomaniac

Reged: 09/26/05

Loc: Amargosa Valley, NV, USA
Re: Beautiful, intriguing, elegant ideas new [Re: CounterWeight]
      #5620021 - 01/12/13 11:37 PM

If they ever launch a warp-drive spaceship, I hope they break a Klein bottle across the bow.

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Rick Woods

Reged: 01/27/05

Loc: Inner Solar System
Re: Beautiful, intriguing, elegant ideas new [Re: llanitedave]
      #5620053 - 01/13/13 12:11 AM

The drive will be powered by a 4D hamster running on a Mobius treadmill. (Dilithium crystals - ha!)

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