🚀 go-pugleaf

RetroBBS NetNews Server

Inspired by RockSolid Light RIP Retro Guy

Article View: sci.physics
Article #4757

Re: Covariant vs. Lie Derivative in Gen. Rel.?

#4757
From: Andrew Stanford Klingler
Date: Wed, 11 Nov 1992 21:40
22 lines
1636 bytes

JB:

>
>To repeat: The connection allows you to compare tangent vectors at two
>points of the manifold given only a curve connecting them; the Lie
>derivative requires a whole vector field, to generate a flow that "drags
>tensors along". 
>
The distinction you're making sounds kind of phony; after all one can
define a connection using a vector field or a field of one-forms (I may
be limiting myself to principal fiber bundles here).  It seems like the
flow is just buried in the structure for a connection (in some sense a
connection gets you "more than a flow" - the local family of geodesics
through a point).  Without a connection, you have no way to compare vectors
at two different points, so you have to transport tensors out, then back
to the same point and compare them there.  With a connection, you have
"flow in every direction" (geodesics thru the point) so parallel transport
vectors from a point to any other point and compare them there.  From this
point of view Lie derivatives and covariant derivatives represent the
same geometric thing, I think.  Am I way wrong here?
Technical Details
Message-ID: <1drukoINN801@darkstar.UCSC.EDU>
Path: arc1-ca.pugleaf.net!sparky!uunet!think.com!ames!agate!darkstar.UCSC.EDU!ucscb.UCSC.EDU!ask
References: <1992Nov10.173224.6690@vision.ummed.edu> <1992Nov11.062853.22717@galois.mit.edu>

Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!sparky!uunet!think.com!ames!agate!darkstar.UCSC.EDU!ucscb.UCSC.EDU!ask
From: ask@ucscb.UCSC.EDU (Andrew Stanford Klingler)
Newsgroups: sci.physics,sci.math
Subject: Re: Covariant vs. Lie Derivative in Gen. Rel.?
Date: 11 Nov 1992 21:40:40 GMT
Organization: University of California; Santa Cruz
Lines: 24
Sender: ask@ucscb.ucsc.edu
Message-ID: <1drukoINN801@darkstar.UCSC.EDU>
References: <1992Nov10.173224.6690@vision.ummed.edu> <1992Nov11.062853.22717@galois.mit.edu>
NNTP-Posting-Host: ucscb.ucsc.edu