domingo, 23 de noviembre de 2008

Relatividad especial

Imaginemos que dos personas que caminan lentamente se cruzan en la calle. Los sucesos en la galaxia Andrómeda (la galaxia importante más cercana a nuestra propia Vía Láctea, a unos 20 000 000 000 000 000 000 kilómetros de distancia), que las dos personas juzgan simultáneos con el momento en que ellas se cruzan, podrían tener una diferencia de varios días. Para una de las personas la flota espacial lanzada con el intento de acabar con la vida en el planeta Tierra está ya en camino; mientras que para la otra, la decisión sobre si enviar o no esa flota ¡todavía no se ha tomado!

Estoy realmente extasiado leyendo este libro, creo que nunca en mi vida había comenzado a entender tanto sobre las teorías modernas de la física. Hace falta que el lector ponga atención y cuidado de su parte pero, wow, las explicaciones de Penrose son de verdad geniales.

De verdad que ni la magia ni la ciencia ficción me pueden emocionar tanto como la ciencia de verdad.

miércoles, 5 de noviembre de 2008

The elecetion that was lost

Proposition 8. I thought that humanity was already moving forward and away from irrational homophobic stances. Apparently, we aren't there yet.

Also declined the two propositions on Renewable Energy and Alternative Fuels. Makes me feel that people are failing to see which are the really important issues we're facing today.

domingo, 2 de noviembre de 2008

Mi vida reciente

Estos merecían ser varios posts independientes, pero viendo que nunca tendré tiempo para escribirlos, mejor pondré algunos resúmenes de lo que me mantuvo ocupado el mes pasado.
  • Varios grupos de investigación en verificación en Alemania nos juntamos en un ‘workshop’ en Alaçatı, Turquía para exponer nuestros trabajos y compartir ideas. La verdad es que si fue en verdad bastante trabajo, con pláticas de 9am a 9pm todos los días. Con un descanso al medio día para comer, pero que varios de nosotros aprovechamos para ir a hacer algo de windsurfing que es, aparentemente, la actividad turística por excelencia de Alaçatı.
  • Me rechazaron un paper donde tratábamos de exponer (sin mucho éxito) ideas para verificar aplicaciones que trabajan conectadas a redes de cómputo. Identificamos que parte del problema es el lenguaje usado para describir a estas aplicaciones, y enviamos un nuevo paper proponiendo mejoras a dicho lenguaje. Este segundo paper fue aceptado en PADL'09, un workshop que se celebrará en enero en Savannah, Georgia, USA.

    Ahora la parte interesante: los diseñadores originales del lenguaje también tienen un paper aceptado en el mismo workshop y, por el título, parece que ellos si pudieron hacer algo de verificación. Ahora estamos un poco estresados, tratando de obtener también resultados nuevos, y someterlos a publicación lo antes posible. Enero va a ser un mes interesante.

  • Ale pasó sus últimos días aquí en Saarbrücken antes de irse a Dublín para estudiar el doctorado. Como ella no había ido aún a Luxemburgo, y ya que está prácticamente aquí a dos pasos, decidimos que sería buena idea aprovechar y nos fuimos a dar una vuelta por aquella hermosa ciudad. Trivia: (1) aunque en las calles se habla Alemán y Frances, su idioma oficial es Luxembourgish, (2) todo el centro de la ciudad está cubierto por wi-fi gratuito provisto por el gobierno.

viernes, 24 de octubre de 2008

Routing on flat labels

Caesar, M., Condie, T., Kannan, J., Lakshminarayanan, K., and Stoica, I. 2006. ROFL: routing on flat lables. SIGCOMM Comput. Commun. Rev. 36, 4 (Aug. 2006), 363-374.
I'm sure the reviewers found their work rather amusing. :-P

domingo, 12 de octubre de 2008

Madness and Genius

One of my favorite comics is Abstruse Goose, which often shows a mix of science, math and humor. Great stuff! But I was rather surprised by the latest comic, The Cantor Madness, which somehow plays with the idea that some things “aren't meant to be comprehended by finite minds”. The comic also included links to a BBC documentary Dangerous Knowledge by independent filmmaker David Malone.

The film is quite interesting, it describes some of the amazing work of Georg Cantor (on infinity in mathematics), Ludwig Boltzmann (on statistical thermodynamics), Kurt Gödel (on the incompleteness theorem in logic) and Alan Turing (on computability and the halting problem). I learned many interesting things, I was familiar with the work of Cantor but not so much with his life. I also didn't knew too much about the work of Boltzmann.

On the downside, all of the movie somehow speculates that the power of the ideas that these persons were developing in their minds also caused them, well, to go insane. In particular, as well as the comic shows, it is lightly suggested that trying to prove the continuum hypothesis will literally drive you crazy. And we have seen this before. Other movies, such as A Beautiful Mind and very explicitly Pi, play with the similar concept of ideas so powerful that can effectively break your mind.

Coming back specifically to BBC's documentary, it is true that all of these scientists often had problems with depressions, in particular both Boltzmann and Turing ended their lives by suicide. But the hints of the movie trying to connect their work and ideas with their mental problems are very misleading.

Coincidentally, I've just finished reading a biography of Gödel, so I can shed some light on that. Gödel actually had problems with depression and hypochondriasis throughout all of his life. Not related at all with him trying to prove the continuum hypothesis, his mental illness gradually developed by many factors such as stress, a lot of pressure from responsibilities at work, and the death of close friends (Einstein being one of them).

The other interesting case is Alan Turing. He didn't really suffered from any strong depression or mental illness. He was an homosexual at a time where, in the U.K., homosexuality was regarded as illegal and a criminal offense. As an alternative to jail, Turing was given the option to undergo hormonal treatment with estrogen hormone injections to reduce his libido. His dead had certainly more to do with this prosecution than with the genius and reach of his ideas.

Also disappointing is the fact that the movie never mentions that the continuum hypothesis has been resolved. And the solution is no less exciting than the incompleteness theorem and the halting problem themselves. For those who haven't heard about it before, here is a very quick description of the problem. It turns out, as Cantor showed, that there are infinities of different sizes. In particular, he showed that there are more real numbers than there are natural numbers. The question is then: is there an infinite set whose size is larger that that of natural numbers but smaller than that of real numbers?

Well, as Paul Cohen proved by concluding the work of Gödel, the answer is: whatever you like. More formally he showed that the answer is independent from the axioms of set theory (as given by Zermelo–Fraenkel). So you can assume that there are no infinite sets between natural and real numbers, be happy with that, and prove theorems; in very much the same way in which you can assume that there are infinite sets between natural and real numbers, be happy with that, and prove theorems. Isn't that exciting or what?

Anyway, the movie obviously left me with some intrigue. It is true that some of the greatest minds of mankind have suffered from very strong mental illnesses. Is it maybe true that there is somehow a link between the two? I thought that, obviously, someone should have already done a study in that respect and, as I found out, of course many studies have been done. I was initially surprised with the results (after some thought it actually makes sense) since the fact is that yes, there is a correlation, but the correlation is negative.

According to several studies cited in the Intelligence quotient article on Wikipedia, persons with higher IQ tend to suffer less from severe depression, schizophrenia and Post-Traumatic Stress Disorder. Also a higher IQ is correlated with living longer and more healthy. Children with higher IQ also were less likely to suffer injuries that require hospitalization in their adult life. One possible explanation being that they better avoid injury and take better care of their own health.