Date: Apr 24, 2013 11:33 AM
Author: Wade Jenkins
Subject: Re: What is a vector field?

Tom Roberts wrote:

>>> Hmmmm. In physics, where we always have an ORIENTABLE manifold WITH

>> Certainly at an undergraduate level, but once you get into things like
>> gauge theories you need manifolds without a metric.

> Yes. I meant spacetime manifold.

Finally you admit, relativity is an undergraduate level!