# Talk:Frame bundle

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Field:  Geometry

## Vielbein versus veirbein

I've realized the spelling "vielbein" is far more common than "vierbein". Phys 21:31, 12 Dec 2003 (UTC)

"vierbein" refers to frames in four dimensions, "vielbein" refers to frames in many dimensions: the German for four is "vier" and for many is "viel". I hope that helps!

## really?

should these frames not be orthonormal? or does it not matter since you can untwist the fibre locally?

husemoller talks about orthonormal k-frames a bit differently, and there does not seem to be an article talking about that, should it be mentioned here or should we at least point towards the stiefel variety/manifold?-sean, a lowly math student.

## Fundamental vs. solder

I choose to emphasize the name fundamental rather than solder because of the following quote from Sharpe (Differential geometry, 1997, p.363):

[Fundamental forms] have also been called "canonical" or "solder" forms. The terminology depends on the context. When we are given the frame bundle of a manifold, the correct terminology is "fundamental" or "canonical" forms since, as described in the definition, they are canonically determined on the frame bundle. On the other hand, if we are given a principal bundle, then the "solder forms" are not canonical, but once they are given they allow us to uniquely identify this principal bundle with a bundle of frames so that the solder forms correspond to the restriction of the canonical forms. Thus, the solder forms allow us to "solder" (in the sense of "identify") the two bundles.

What do you think? -- Fropuff 16:15, 21 March 2007 (UTC)

This is a reasonable point, although I would then say that the frame bundle therefore has a canonical (or tautological) solder form. Anyway, I don't feel strongly about it (although I think "canonical" and "tautological" are a bit more descriptive than "fundamental"), so do as you think best. Geometry guy 16:50, 21 March 2007 (UTC)

## diagram needed

Actually, I'd rather see a diagram over at fiber bundle to be honest. The discussion of bundle maps is far too short, and definitely needs to be fleshed out with a diagram. But diagrams are a good thing in general, so why not put one here too. Silly rabbit 10:47, 5 May 2007 (UTC)