Name: Flavio Botelho
Member since: 2003-05-13 11:21:53
Last Login: 2010-05-06 19:48:32


Ex-Math Student, Computer Scientist, Programmer for a living
Interests - Foundations of Mathematics, Automated Theorem Proving, Discrete Space Time Models, Typed Lambda Calculus, Functional Programming, Haskell, Philosophy of Physics and of course Programming :)

Recent blog entries by nuncanada

Actually in the model the observers will agree on velocity as percentage of light speed. The difference comes from acceleration. There is a prefered "absolute 0 velocity", and the observer that is closer to it will have its time going faster than the other.

From General Relativity these observers observations should be simmetric.

If we were to measure Gravity's contribution in towers in both poles they should not agree...

That pretty much rules out discrete time models?

Found out a model for a theory of mechanics with discrete time which preserves Lorentz invariance.

Unfortunally it seems break one of Realitivity's axioms, that two observers agree on their relative velocity. And it also ends up creating a prefered frame of reference.

If some spaceship's intruments doesnt agree with our velocity measurements on Earth, someone send me an email :- P

5 Dec 2008 (updated 5 Dec 2008 at 03:10 UTC) »
Dynamic Programming is a nice general procedure to attack some specific exponential algorithms and reduce them to polynomial time. But beware, they aren't usually created taking in mind the symmetries of the problem in question, so they may leave a lot to desire to come close to a algorithm designed with the given problem in mind.

So for instance, matrix chain multiplication which is a textbook example for dynamic programming will give out a O(n^3) algorithm. There are much better algorithms for this problem out there, specifically a O(n*log n) one.

Just after i first was taught about the chain matrix multiplication problem and it's dynamic programming solution i couldn't believe that was the best algorithm that could be done for it. Some days later after trying first to find an algorithm and then looking a lot around the internet i finally found this paper. Thanks Hu and Shing for the great work and taking out my obsession with this problem.

24 Sep 2008 (updated 24 Sep 2008 at 00:46 UTC) »

Am I crazy?

* I believe formal methods (typed lambda calculus, example: Coq) is the path for the future of programming, not all the fashion industry that comes from Software Engineering and business.

* I believe deep down time is discrete (maybe because i have been programming since being 6 years old, and that scrambled my head to disbelieve the continuum?). Even being a maverick in math and physics during school i never liked geometry, I felt uncomfortable with continuity since early on.

* I believe democracy with capitalism and inheritance has always failed, its inefficiency and unfairness in all levels is just absurd. There must be a better social arrangement, and merit has to play a big part of it, not which family you grew into.

* I haven't been able to make myself believe that the discrete logarithm problem doesn't have a polynomial solution. Didn't find an algorithm but the problem just seems to have too much "symmetry".

See? I told you that I am crazy.

13 May 2008 (updated 14 May 2008 at 20:16 UTC) »
A new world for open source is blooming!

Almost everyone is unaware but the seeds of change have been planted! To a better open source community we are going to!
Open Source is a lot of times regarded as an example of Meritocracy in action, but if you read Amartya Sen's article about Meritocracy, you will recognize that most of Open Source projects fit more in his description of a 'static' meritocracy than a 'dynamic' one (my words to resume his thoughts), and Sen shows how what should be regarded as a real meritocracy is the dynamic qualities.
To our rescue comes the knight in his shinning armor, not other than the famous Linus Torvalds! I guess most readers think i am crazy by now, but keep up and maybe it will make sense.
DVCS have been around longer than git but not only by creating a functional open source DVCS, but by evangelizing the benefits of a distributed system he has planted the seeds that will change the future (interestingly for all the democracy and meritocracy fanatics, this necessity came from a "dictatorship").
And GitHub is sign of the changes to come, once oss developers start to rethink forking not as deviating from the community but as a common fact of producing software, the whole community structure will change!
No longer the "core group" will have the overwhelming power, nor will it matter much, probably such a notion will end up existing mostly. We will have the real possibility for the community to choose what to follow from whom, github is a start in that direction.
I am waiting anxiously for the future, a dynamicly meritocratic one for OSS.

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