• Walter Bright (2/2) Dec 11 2008 ... would dare to wear a Maxwell's Equations t-shirt.
• Knud Soerensen (12/15) Dec 11 2008 I actually had a t-shirt which said
• Bill Baxter (33/46) Dec 11 2008 I was thinking the same thing. Maybe it's something that seems more
• Wolfgang Draxinger (9/10) Dec 16 2008 http://upload.wikimedia.org/math/2/a/8/2a875588f083c9242880671dc49ed8d0....
• Gregor Richards (6/6) Dec 11 2008 Would wear a T-shirt with a formalization of the Order of Urinals[1] on ...
• Walter Bright (8/11) Dec 11 2008 Did you ever see the movie "The Cook, the Thief, His Wife and Her Lover"...
• Bill Baxter (4/10) Dec 11 2008 What does it mean when it says "if U=U_t then error"?

Walter Bright <newshound1 digitalmars.com> writes:

... would dare to wear a Maxwell's Equations t-shirt.

http://www.cafepress.com/digitalmars

Knud Soerensen <4tuu4k002 sneakemail.com> writes:

Walter Bright wrote:
 ... would dare to wear a Maxwell's Equations t-shirt.
 
 http://www.cafepress.com/digitalmars

I actually had a t-shirt which said

God said:
<insert Maxwell's equation>
and there was light

But I would not were it today
when I know that Maxwell's equations don't
describe all electromagnetic experiments.

See http://www.scribd.com/doc/4445/quaternionic-electrodynamics

-- 
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"Bill Baxter" <wbaxter gmail.com> writes:

On Fri, Dec 12, 2008 at 6:28 AM, Knud Soerensen
<4tuu4k002 sneakemail.com> wrote:
 Walter Bright wrote:
 ... would dare to wear a Maxwell's Equations t-shirt.

 http://www.cafepress.com/digitalmars

 I actually had a t-shirt which said

 God said:
 <insert Maxwell's equation>
 and there was light

 But I would not were it today

I was thinking the same thing.  Maybe it's something that seems more
appealing to a college student just learning that stuff, but to me it
seems like a fairly boring old set of differential equations now.

 when I know that Maxwell's equations don't
 describe all electromagnetic experiments.

Well, that wasn't quite my reason.

 See http://www.scribd.com/doc/4445/quaternionic-electrodynamics

Interesting.  The other interesting developement these days seems to
be describing things using the math of differential forms and/or
geometric algebra.  Instead of div grad curl, and all that.    Hmm the
biquaternions in your reference seem to be related to this...  I see
both "geometry algebra" and "biquaternions" associated with "Clifford
algebra" in google searches.   Don't really understand all that stuff
myself, but I'm interested in learning more.    The SIGGRAPH course
notes for the Discrete Differential Geometry course have a paper by
Desbrun on differential forms that I was reading through the other
day.
http://www.geometry.caltech.edu/pubs/GSD06.pdf

Here's a quote I just found:
"""
The elegance of geometric algebra is clearly evident in that fact that
Maxwell's equations become a single equation in this algebra.
"""
http://jtauber.com/blog/2004/03/27/geometric_algebra/

And here's that equation, apparently:
http://upload.wikimedia.org/math/2/a/8/2a875588f083c9242880671dc49ed8d0.png

Maybe it doesn't make for quite as interesting a T-shirt though...
but still it puts you one-up over those guys wearing Maxwell's
equations written in component form.  That's sooo passe.  And any
run-of-the-mill nerd recognizes the component form.  To be a true
uber-elite nerd you need to wear the geometric algebra Maxwell's
equation.

Heh.  You make that shirt, and I just might buy it.  :-)

--bb

Wolfgang Draxinger <wdraxinger darkstargames.de> writes:

Bill Baxter wrote:

 And here's that equation, apparently:

http://upload.wikimedia.org/math/2/a/8/2a875588f083c9242880671dc49ed8d0.png

Yeah, that's the covariant formulation of the maxwell equation,
where F is the electromagnetic metric tensor.

And it doesn't really scare me, it's what german physics students
do in their 2nd year.

Wolfgang Draxinger
-- 
E-Mail address works, Jabber: hexarith jabber.org, ICQ: 134682867

Gregor Richards <Richards codu.org> writes:

Would wear a T-shirt with a formalization of the Order of Urinals[1] on it.

http://www.cafepress.com/bizarregeek.318179787

  - Gregor Richards

[1] The Order of Urinals is the algorithm all men implicitly and 
subconsciously use upon entering a bathroom to determine which urinal to 
use.

Walter Bright <newshound1 digitalmars.com> writes:

Gregor Richards wrote:
 [1] The Order of Urinals is the algorithm all men implicitly and 
 subconsciously use upon entering a bathroom to determine which urinal to 
 use.

Did you ever see the movie "The Cook, the Thief, His Wife and Her Lover" 
? It was a terrible, awful movie, but there was one scene that I burst 
out laughing at. It was the scene in the bathroom. My date was 
perplexed, obviously not knowing the Code of the Urinal. They were 
situated in a circle in that bathroom, so you had no choice but to look 
at the other men using it.

I suppose a movie can't be all bad if it pried one good laugh out of me <g>.

"Bill Baxter" <wbaxter gmail.com> writes:

On Fri, Dec 12, 2008 at 4:00 PM, Gregor Richards <Richards codu.org> wrote:
 Would wear a T-shirt with a formalization of the Order of Urinals[1] on it.

 http://www.cafepress.com/bizarregeek.318179787

  - Gregor Richards

 [1] The Order of Urinals is the algorithm all men implicitly and
 subconsciously use upon entering a bathroom to determine which urinal to
 use.

What does it mean when it says "if U=U_t then error"?
Is that when you get confused and accidentally pee on another guy?

--bb