<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=us-ascii"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
h1
{mso-style-priority:9;
mso-style-link:"Heading 1 Char";
mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:24.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
span.Heading1Char
{mso-style-name:"Heading 1 Char";
mso-style-priority:9;
mso-style-link:"Heading 1";
font-family:"Times New Roman","serif";
mso-fareast-language:EN-GB;
font-weight:bold;}
.MsoChpDefault
{mso-style-type:export-only;
font-family:"Calibri","sans-serif";
mso-fareast-language:EN-US;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Dear Gregory Woodhouse<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Unrelated to Racket – I’m interested in the Geometry of 2 Complex Dimensions (“G2CDs”) and came across your 2006 post: <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><h1 style='margin-left:72.0pt'><span style='font-size:12.0pt'>[plt-scheme] 3rd-8th Grade<o:p></o:p></span></h1><p class=MsoNormal style='margin-left:72.0pt'><b>Gregory Woodhouse</b> <a href="mailto:users%40racket-lang.org?Subject=Re:%20Re%3A%20%5Bplt-scheme%5D%203rd-8th%20Grade&In-Reply-To=%3CC2FB68FC-173F-486D-89BC-C805CDEC43C2%40sbcglobal.net%3E" title="[plt-scheme] 3rd-8th Grade">gregory.woodhouse at sbcglobal.net </a><br><i>Mon Mar 20 08:51:15 EST 2006<o:p></o:p></i></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>As it appears that you know something about the G2CDs, would you be able to point me towards any fairly elementary book/article that discusses it?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m an ex-chemist (but not a mathematician) trying to obtain some intuitive insight into spinors, and came across Bruce Schumm’s “Deep Down Things” (a popular level explanation of gauge theory) in which he starts discussing rotations in 2CDs. Rather than limiting it to the usual discussion of the Lie group SU(2), he does start to explain it in a bit more detail, and I’d very much like to pursue this, but he gives no references. I’m well aware of the common references to spinors, quaternions, Clifford algebras, and geometric algebra, but with one very limited exception, haven’t found any description, at the level of coordinates etc., of the type I seek.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I would be most grateful for any constructive advice <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Paul Ellis<o:p></o:p></p><p class=MsoNormal><b><span lang=EN-US style='font-size:8.0pt;font-family:"Verdana","sans-serif";color:black'>_________________________________<br><br></span></b><b><span lang=EN-US style='font-size:7.0pt;font-family:"Verdana","sans-serif";color:black'>Paul G. Ellis (Dr) | Teaching & Research Co-ordinator | Management Science & Operations</span></b><span lang=EN-US style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:gray'>London Business School | UK | Email <a href="mailto:pellis@london.edu"><span style='color:gray'>pellis@london.edu</span></a> <br>+ 44 (0)20 7000 8835 | Mob: 0776-191-3270 </span><span lang=EN-US style='color:#1F497D'><br><a href="http://www.london.edu/" title="http://www.london.edu/"><span style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:gray'>www.london.edu</span></a></span><span lang=EN-US style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:gray'> | Thought leadership. World impact.</span><span lang=EN-US style='font-size:7.0pt;color:black'> </span><span lang=EN-US style='font-size:7.5pt;font-family:"Verdana","sans-serif";color:black'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div><BR>
______________________________________________________________________<BR>
<BR>
This email has been scanned by the MessageLabs Email Security System<BR>
on behalf of the London Business School community.<BR>
For more information please visit http://www.messagelabs.com/email<BR>
______________________________________________________________________<BR>
</body></html>