C9 Lectures: Dr. Brian Beckman - Covariance and Contravariance in Physics 1 of 1

Posted By: Charles | Nov 25th, 2009 @ 10:22 AM | 61,826 Views | 30 Comments
By now, you know Brian Beckman given how many times he's been featured on Channel 9 and, well, just how amazing he is. Brian is an astrophysicist and software architect currently working on a technology we can't talk about...yet... Smiley Stay tuned for that. Dr. Beckman is the perfect choice for a new lecture in the C9 Lectures series. This is a single lecture, but there will be more interesting conversations to come on this deep and beautiful topic (in some sense, this is all about symmetry).

In the Rx interview with Brian and Erik Meijer, a short discussion on covariance and contravariance took place as a tangential topic (which often happens in real conversations - and we love that!). The concepts of co/contravariance can confuse and confound. Also, they are not just related to programming.

Here, Dr. Beckman teaches us about covariance and contravariance in physics. Are these universal properties? Do they apply to the mathematics of physics (from quantum mechanics to black holes) in the same basic way they do for general purpose programming with objects and lists, for example?
 
Tune in. This is a deep dive lecture and quite mathematical. Don't be scared. As usual, Brian explains complex things in a readily understandable fashion for mere mortals. If you have no experience with math and physics, this may be a bit challenging, but certainly not entirely over your head.

Enjoy.

NOTE: You should download the supporting document and slides (you should download the MathType fonts here). This will help you learn faster!
Rating:
11
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#Nov 25th, 2009 @ 12:56 PM
N2Cheval
N2Cheval
Why not null?

I'm getting the error "Media Failure. Try reloading the page or visiting the main site for assistance." when watching throught the browser.

#Nov 25th, 2009 @ 1:00 PM
Charles
Charles
Welcome Change

This could be due to transient networking issues on your network. It works fine for me on my home DSL via Earthlink... The files are on the servers Smiley

 

What version of Silverlight are you using? Which browser?

 

What happens when you click Media Downloads and choose WMV?

C

#Nov 25th, 2009 @ 2:06 PM
dot_tom
dot_tom

Awesome! I never thought we'd actually get to hear Brian riff on this topic, it's great that MS and C9 give their uber brains the time and platform for these kinds of videos. This has been a vintage year for Channel 9 and it's merry band.

#Nov 25th, 2009 @ 2:14 PM
Richard.Hein
Richard.Hein
Stay on Target

The video stops playing whenever I try to go full screen in the browser.  Windows 7, IE8.

#Nov 25th, 2009 @ 4:38 PM
Charles
Charles
Welcome Change

This may be a bug with our player. We will look into this. For now, download the high res version and enjoy full screen in Windows Media Player.

C

#Nov 25th, 2009 @ 4:46 PM
Charles
Charles
Welcome Change

This topic is entirely original, by the way. Brian wrote the attached document that provides much greater detail, mathematically, for the beautiful story Brian is telling. Do read it.

 

In some sense, the physical world is composed of monadic symmetric fractal structures. Well, that's what Brian's thinking and writing evoked in my simple mind Smiley

 

And thank you for the kind words. I have to agree with you: this is the best year in C9's history and the new team is the best ever. I've been a member of all iterations of the C9 Team and this group simply represents the most creative and capable to date. Further, the content quality (and quantity) that is created by folks not on the C9 Team is just stellar. I'm loving this.

 

You will see and hear Brian again on Friday as he talks to me about Complexity in the latest edition of C9 Conversations. C9 Conversations is a new series that will focus on big problems and the big brains trying to solve them - all in a conversational, well-produced, unscripted, real way. Consider it C9 Classic++

 

Cheers,

C

#Nov 25th, 2009 @ 6:17 PM
wil2300
wil2300
Super #

His interview with Erik on Rx was wicked. Looking forward to this one!

#Nov 25th, 2009 @ 8:16 PM
brianbec
brianbec

I'm working on the concept that a monad is a "coordinate system," and that going from one monad to another is analogous to a coordinate transformation. If this concept is right, then covariance and contravariance will just "fall out" the way they do in physics. A good friend of mine has shown me how to do the "chain rule" in the lambda calculus, so I think we can close this all up. It will be a LOT of calculations, but calculations are fun and a really great way to do proofs Smiley  We'll see if this works out.

#Nov 25th, 2009 @ 10:49 PM
Charles
Charles
Welcome Change

I sense more lectures, dear Brian Smiley

 

Cheers,

C

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