Russell Standish wrote circa 07/14/2010 02:09 PM: > On Tue, Jul 13, 2010 at 10:07:14PM -0600, Roger Critchlow wrote: >> Working from the context, I'd guess: the tensor product between the >> components <i>dx<sup>a</sup></i> and <i>dx<sup>b</sup></i>of the stress >> energy tensor <i>T<sub>ab</sub></i>, but I've never been too sure about >> tensors. >> > > Not a tensor product, but an exterior product. It's somewhat related to > a cross product of two 3D vectors.
Thanks for all the answers! It's interesting to me that this page: http://en.wikipedia.org/wiki/Differential_form#Wedge_product is less understandable to me than this page: http://mathworld.wolfram.com/WedgeProduct.html which is _less_ understandable to me than this page: http://en.wikipedia.org/wiki/Exterior_algebra A usual, each answer is different enough to provide a parallax. I always wonder what it would look like to circumscribe my (or anyone's) knowledge (or, at least, familiarity). Would the surface of such a circumscription have a very rough texture? Or would it be smooth[ish]? Would it have great big divots? Would the "things one knows (of)" even form a connected set? Everyone talks about wise people knowing when they don't know something. That seems easier said than done. ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
