Comments for 4by12

Comment on Legendre Transform by sivaramakrishnan

sivaramakrishnan — Mon, 19 Oct 2009 12:34:12 +0000

nice post!

Comment on No More Time Waste by sandrar

sandrar — Thu, 10 Sep 2009 14:28:37 +0000

Hi! I was surfing and found your blog post… nice! I love your blog. Cheers! Sandra. R.

Comment on How to push GMail, Twitter to your iPhone with Prowl by Anonymous

Anonymous — Tue, 11 Aug 2009 14:22:42 +0000

Yes, I guess it’s the right thing to do, even though it’s a bit embarrassing.

Comment on How to push GMail, Twitter to your iPhone with Prowl by Stephan

Stephan — Thu, 06 Aug 2009 14:10:45 +0000

Very cool. Thanks for the patch of Net::IMAP::Client, although inelegant. Maybe you want to submit the patch to the original author?

Comment on A Short Note on the Poincaré Algebra by Dan Elharrar

Dan Elharrar — Mon, 25 May 2009 10:44:34 +0000

To me, and to generations of French kids, there is only one Casimir.

Comment on Correct arXiv authors in Google Reader by ggg

ggg — Tue, 19 May 2009 09:31:11 +0000

thanks for this, I have been waiting for ages for Google to fix this problem!

Comment on Complex Square Root by Guy Gur Ari

Guy Gur Ari — Tue, 24 Mar 2009 15:16:51 +0000

Yes of course. Perhaps the post was not clear. My only point is this: With the reals, the mistake is easy to spot. More importantly, one can work with a definition (sqrt = positive root), using which algebra behaves as you expect.

With the complex numbers the mistake is more subtle, and there is no such convenient definition for sqrt. Seemingly innocent manipulations often conceal mistakes, as one must always be careful when crossing the branch cut.

Comment on Complex Square Root by jascha

jascha — Tue, 24 Mar 2009 10:24:28 +0000

uh-oh. I think it might be spreading to the reals! Proof that 1 = -1:

sqrt(1) = 1
sqrt(1) = -1

1 = sqrt(1)/sqrt(1) = 1/-1 = -1

Comment on Legendre Transform by jascha

jascha — Tue, 24 Mar 2009 10:19:46 +0000

Thanks for writing this up! I found it really helpful.

Comment on It’s like deja vu all over again by Guy Rosen

Guy Rosen — Thu, 13 Nov 2008 09:24:56 +0000

Looks like it’s burst