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

http://www.cafepress.com/digitalmars

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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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

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.

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>.

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

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
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