## Thursday, October 13, 2005 ... //

### Derived categories: what Joe hears

Melanie Becker (via Katrin Becker) has pointed out an interesting talk showing what dogs hear when we tell them something - and analogously, what Joe hears when someone speaks about derived categories. ;-) Well, Joe is not quite the only person with this kind of hearing.

Incidentally, it has just become possible for loop quantum gravity to solve problems related to the Pythagorean theorem.

#### snail feedback (5) :

I wonder if this is a good place to post this? :-)

Dear Belette,

Please keep this kind of news away from this blog, which Lumos is keeping respectable.

I don't think it very funny to make fun of string theorists. That link made me cry ...

Lumos has integrity, as does Lisa Randall. I think it deplorable that this month's Scientific American, Oct issue, takes the mickey out of Lisa.

It is very unkind of them to put the caption "Lisa Randall: Warped Thoughts" under her picture in an article headed "Branes are Beautiful" or whatever.

Lumos is not responsible for the crisis in string theory, despite proof-reading drafts of Lisa's book "Warped Passages" which was published last month.

I have on occasion taken issue with Lumos when he has asserted things which are incorrect (such as the claim that string theory has something to do with science), but I don't think you need to make people weep by putting links on his comments to spoof articles on string theory. Then again, perhaps I'm wrong.

By the way, your kids look delightful.

Have a nice day!

Nigel

Dear Nigel,

thanks for your support but I will personally forgive Belette this joke. As the picture shows, Belette just drank some milk and then wanted to have some fun. I hope his brother and father will forgive him, too.

The link to that spoof article was a main text on cosmicvariance.com ;-). I personally liked the Onion article on Bush who found the errors in semileptonic decays here.

best
Lubos

Dear Lumo,

Ouch! Dr George Bush is far better at armchair physics than I am: "reducing the perturbative uncertainty in the determination of V(subscript: ub) from semileptonic Beta decays, one must calculate the rate of Beta events with a standard dilepton invariant mass at a subleading order in the hybrid expansion. The Fermilab folks' error, as I see it, was omitting that easily overlooked mathematical transformation and, therefore, acquiring incorrectly re-summed logarithmic corrections for the b-quark mass. Obviously, such a miscalculation will result in a precision of less than 25 percent in predicting the resulting path of the tau lepton once the value for any given decaying tau neutrino is determined."

Wow! How embarrassing it must feel to have math errors exposed by a professional politician. At least President Bush is a president. (It would be much worse to have the errors exposed by a load of crackpots from computer engineering and writers of crazy electronics magazine articles, who don't even know QFT perturbative theory but think they can work out a semi-classical version just by guessing it from electrodynamics.)

I love the fact that Dr John Baez, who has a nice online description of GR maths at http://math.ucr.edu/home/baez/gr/outline1.html thinks he has the right to give cranks a "5 point starting credit", see:

http://www.phys.psu.edu/~scalise/misc/crackpot/crindex.html

This means that everyone he merely decides to evaluate for crackpotism, starts with 5 points regardless of the theory. This is unfair to string theorists! ;)

Best wishes,
Nigel