From mboxrd@z Thu Jan 1 00:00:00 1970 To: 9fans@cse.psu.edu From: "Thomas Bushnell, BSG" Message-ID: <87bsfbolpu.fsf@becket.becket.net> Content-Type: text/plain; charset=us-ascii References: <3C561EC9.88F86501@null.net>, <15446.32000.710318.879017@nanonic.hilbert.space>, <3C57AF73.727F8CE9@null.net> Subject: Re: [OT] Re: [9fans] Getting started in Plan9 - help Date: Wed, 30 Jan 2002 16:35:34 +0000 Topicbox-Message-UUID: 4963a288-eaca-11e9-9e20-41e7f4b1d025 "Douglas A. Gwyn" writes: > As usually defined the c.p. is supposed to result in the same > type as its arguments, but e.g. the c.p. of two vectors is > *not* a vector (it's a so-called pseudo- or axial vector, > which can indeed be thought of as a *component* of the tensor > product). So while it might be a "product" it is not as nice > as the kinds of products that map from space x space into space. > The "non-conservation of parity" work that was awarded a Nobel > prize seems to actually have been confusion on this very score. Sure enough. The cross product as tensor-product-with-volume-element makes this even clearer; the result of the "product" is actually a higher rank tensor than the arguments.