So I guess the obvious first answer to my question is: "well it all depends what you mean by a gauge theory".

Agreed. Try this from an amateur:

*A physical theory will be a gauge theory if it is invariant under arbitrary*. This seems to imply our theory is a field theory, but I am happy to be corrected here.

**local**symmetry transformationsNow I am hampered somewhat by the fact the only field theories that I have even nodding acquaintance with are electromagnetism and GR. Certainly, or so I believe, my

*ad hoc*definition applies equally to both.

Now following Drs Yang and Mills, we have a rather richer structure for EM than we do for GR. Specifically, that Yang-Mills gauge theories are modelled on principal bundles, whereas GR, at least in its usual formulation is not - though I can convince myself (with great deal of woolly thinking) that it might be.

Moreover, whereas the curvature in a Yang-Mills theory is a function (via the covariant derivative) of the connection, which is the

*field*of Yang-Mills potentials. in GR the curvature has almost nothing (?) to do with the connection, which is not a field of any description rather curvature is a function of the metric.

So, let's say, for the sake of discussion (or not), that GR is a gauge theory, but not a Yang-Mills gauge theory.

Anyhoo, I asked a question.....why am I rambling on like this?