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Impressions from SPUC09

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SPUC09 was an event that was organized by Mark Hogarth and Mike Stannett and it was founded by EPSRC . It attracted researchers from Computer Science, Mathematics, Physics, Biology, Artificial Intelligence, Economics, and Phylosophy. Delagates presented interesting ideas and the discussions that followed each presentation were very vivid. Personally, I had the chance to meet some new friends and to discuss with them some interesting ideas. Also, I had the chance to personally meet people with whom I had exchanged many e-mails in the past.

Black hole evaporation

Recently, István Németi pointed out to me that there is an omission in my book regarding the feasability of his relativistic hypercomputer. In particular, the following passage In 1974, Stephen William Hawking [80] proposed that black holes emit thermal radiation, now known as Hawking radiation, due to quantum effects. Thus, any black hole will vanish sometime in the future. If Hawking radiation is indeed a real phenomenon, then it is possible that a relativistic computer G will not be able to finish a particular supertask it was assigned to finish. The reason is that the black hole that the computer orbits around might evaporate years before the computer completes its task. Moreover , Hawking radiation should play a role in cases in which the black hole has very small mass. For instance, a black hole of one solar mass will evaporate in 10 67 years, while a black hole of 10 16 kg will evaporate in 3 billion years. the word Morov...

"How to Program an Infinite Abacus"

Joachim Lambek wrote an interesting paper entitled "How to Program an Infinite Abacus" which was published in the Canadian Mathematical Bulletin . Unfortunately, this paper is currently not available in any form. For the benefit of all those people who might like to have a look at this paper, I have prepared a transcription of this paper which is available here .

SPUC09 Conference

The " Science and Philosophy of Unconventional Computing " (SPUC09) conference will take place in Cambridge,UK, March 23-25, 2009. People interested in either attending or presenting their own work should consult the conference's web page.

A comment on a comment

Recently, "someone" posted a review of my book on hypercomputation on the Brains site. The reviewer argues that This area is full of problems, some of which are physico/mathematical and some of which are conceptual. Unfortunately, from a quick sample, Syropolous's book does not avoid common mistakes and confusions—some of which I've been trying to correct in my own work. First of all, I have to admit that back in 2004 I read a paper by this reviewer, but at that time I did not considered it interesting. However, after I read this review of my book, I read The Physical Church-Turing Thesis: Modest or Bold? , the reviewer's latest manuscript, in order to see what he meant by common mistakes and confusions and how he was trying to solve them. In this manuscript, the reviewer puts forth a number of criteria that every machine has to satisfy in order to be ``useful for physical computing.'' These criteria are: Readable Inputs and Outputs Process-Independ...

Hypercomputation and Physical Reality

Konstantine Arkoudas argues in " Computation, hypercomputation, and physical science " why in his opinion [T]he idea that physical science will be able to discover fundamental computability limits is untenable. A computation is carried out by concrete computational devices whose operation and capabilities are delimited by the laws of physics. It is one thing to argue that we have no idea what are the limits of computation and another to simple say that the limits of computation have nothing to do with physical reality. On the other hand, it is more than sure that there is a limit to what we can achieve with computing devices , but for the time being we simply do not know this limit. And this is exactly the essence of hypercomputation.

Landau levels and Riemann zeros

German Sierra and Paul K. Townsend have recently presented an idea that may lead to the solution of the Riemann hypothesis. The Riemann hypothesis is a co-recursively enumerable problem (roughly, there is an algorithm that, when given an input number, eventually halts if and only if the input satisfies the problem, but no algorithm can decide if an arbitrary input satisfies the problem or not). The solution of this and other similar problems would falsify Church's Thesis. Interestingly, Fermat's last theorem and Poincaré's conjecture are co-recursively enumerable problems, nonetheless, these problems have been decided! A proof that Church's thesis is false...?