From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15447.54321.120322.757656@nanonic.hilbert.space> From: paurea@gsyc.escet.urjc.es To: 9fans@cse.psu.edu Subject: Re: [OT] Re: [9fans] Getting started in Plan9 - help In-Reply-To: <3C57AF73.727F8CE9@null.net>:Douglas A. Gwyn's message of 09:29:18 Wednesday,30 January 2002 References: <3C561EC9.88F86501@null.net> <15446.32000.710318.879017@nanonic.hilbert.space> <3C57AF73.727F8CE9@null.net> Date: Wed, 30 Jan 2002 12:08:33 +0100 Topicbox-Message-UUID: 49247608-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, Well, as everything, depends on what you call type. Everything here are Tensors at least. (and also vectors, because tensor spaces are vector spaces). Anyway I think you confusing the c.p. with the wedge product which is it's dual in an special case. As far as I know the c.p. of two vectors is a vector. In fact, it is the special case of aplying the dual operator to the wedge product with N=3 and r=2, that is, the result is also a vector in the same space, that is why it is called vector product too. The tensors which written as a wedge product form a tensor are called its strict components (I think you are referring to that). Anyway, the wedge product of a group of tensors is a tensor too. And *all* of this operations are called products, though that is exterior algebra and maybe the analogy has been taken a little bit too far. -- Saludos, Gorka "Curiosity sKilled the cat"