Path: csiph.com!weretis.net!feeder6.news.weretis.net!nntp.club.cc.cmu.edu!micro-heart-of-gold.mit.edu!bloom-beacon.mit.edu!bloom-beacon.mit.edu!panix!panix.com!forkosh From: JohnF Newsgroups: comp.lang.postscript Subject: Re: hypercube rotations Date: Sat, 16 Jul 2016 05:01:20 +0000 (UTC) Organization: PANIX Public Access Internet and UNIX, NYC Lines: 49 Message-ID: References: <46e56073-6c7b-416e-8733-a2fe836c3a71@googlegroups.com> <9f79426f-2e3b-475d-a98e-b6f9ec215ec6@googlegroups.com> NNTP-Posting-Host: panix3.panix.com X-Trace: reader1.panix.com 1468645280 22164 166.84.1.3 (16 Jul 2016 05:01:20 GMT) X-Complaints-To: abuse@panix.com NNTP-Posting-Date: Sat, 16 Jul 2016 05:01:20 +0000 (UTC) User-Agent: tin/1.6.2-20030910 ("Pabbay") (UNIX) (NetBSD/6.1.5 (i386)) Xref: csiph.com comp.lang.postscript:2705 luser droog wrote: > On Friday, July 15, 2016 at 7:14:09 PM UTC-5, JohnF wrote: >> Peter Billam wrote: >> > On 2016-07-08, luser droog wrote: >> >> A year or two ago I tried to beef-up my vector analysis skills >> >> by reading the very interesting History of Vector Analysis. >> >> I can now spell Ausdehnungslehre, but I never figured out how >> >> to do a Grassman product. Quaterions freak me out. For that >> >> matter, the complex plane still freaks me out. I think I need >> >> to take a math class. >> > >> > The most helpful intro to Grassman products I know is >> > Roger Penrose "The Road To Reality" pp.211-215, 227-229. >> > He's a great explainer, but it's a heavy book, 1094 pages... >> > Not that I've ever actually _used_ a Grassman product :-) >> > The complex plane is not scary, in fact Roger Penrose mostly >> > exists in the complex plane. He introduces it in pp.81-83,87-88... >> >> That's a terrific book, uniquely filling an otherwise empty niche, >> introducing a lot of significant "mathematics for physicists" >> for readers without all the usual prerequisites. You do need >> enough background so as not to get scared just looking at math, >> but then you come away really knowing some stuff. (Sometimes >> I find him a bit too wordy with tangential prose, unnecessarily >> interrupting the main stream of concepts to the point you can >> lose track of what you were doing.) >> >> > Wikipedia is really authoritative in this kind of thing, >> > but it's often overwhelming, and >> > https://en.wikipedia.org/wiki/Exterior_algebra >> > is a example of that :-( Regards, Peter >> > P.S. I've never used a quaternion either, and mainly know them from >> > http://math.ucr.edu/home/baez/octonions/ >> > by John C. Baez >> >> He's done some really good work, too, and put up a lot of good >> stuff on the web. Two nice references, pjb. > > Thanks, fellows! Wikipedia also led me to this free textbook: > "Linear Algebra via Exterior Products" (2010) by Sergei Winitzki. > https://sites.google.com/site/winitzki/linalg > which I will be reading while amazon does its thing. Penrose is also free online, http://chaosbook.org/library/Penr04.pdf (which I hesitated to mention earlier since it's pretty obviously pirated) -- John Forkosh ( mailto: j@f.com where j=john and f=forkosh )