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Charles Stewart's user avatar
Charles Stewart's user avatar
Charles Stewart's user avatar
Charles Stewart
  • Member for 14 years, 11 months
  • Last seen more than 6 years ago
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Weakest subsystems of second order arithmetic for mathematical logic
But Simpson's book does not discuss the literature on base theories weaker than RCA-0, so this answer does not really address the question.
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Is there a progress on a solution of the inequality $\pi (m+n) \leq \pi (m) + \pi (n)$
Does language like "elevate ... obvious" and "explode" indicate some hostility to Hardy or Littlewood?
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Are real numbers countable in constructive mathematics?
Bishop's constructive mathematics has the property that if you prove something, then you can algorithmically extract a constructive witness to it. To slightly oversimplify, the witness to a real number will be a program generating a converging sequence of intervals (pairs of rationals). I'd call that algorithmic.
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Do you know any good introductory resource on sequent calculus?
@Sergei: I'd recommend getting the book, Negri & von Plato, 2001, Structural proof Theory to someone who wants to study this approach, which emphasises the generalised elimination rules of Schröder-Heister, cf. e.g., www-ls.informatik.uni-tuebingen.de/psh/forschung/publikation‌​en/…
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The Importance of ZF
@Todd: I did not find the discussion shallow, and I did not find Friedman to be hostile, although I entirely agree that Simpson framed the whole issue in a pointlessly divisive manner: the list-1 vs. list-2 distinction was presented almost as a matter of moral character. I agree that justice was not done to the structuralist viewpoint, but I still think that Friedman is right to say that categorical logicians (among others) have not presented a genuinely independent ontology for mathematics that achieves what modern set theory does.
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What are the most fundamental classes of mathematical algorithms?
I think the intent of the question is a good one, but this is a bit of a Celestial Emporium of Benevolent Knowledge approach to categorisation. "Euclid" covers a pretty diverse bunch of things, if it covers any technique found in the Elements.
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Stone Spaces, Locales, and Topoi for the (relative) beginner
This book is tough for those without the right kind of mathematical background. It took me a long time to work through chapter two.
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The Importance of ZF
@David: Maclane's categorical set/type theories are not foundationally complete, in Friedman's sense.
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How to correct an error in a submitted paper?
@Kevin: Would you be happier if, instead of a revised version, an erratum, detailing by page/line the problems in the paper, were sent? This eliminates the risk of confusion over what is being reviewed.
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How to correct an error in a submitted paper?
One of my early refereeing mistakes was to do exactly this: after I finished writing my report on the paper with the same title I downloaded from the author's site, I took a look at the paper I had been emailed, to note that this paper was completely different: I had to largely rewrite my report, and changed my recommendation from reject to accept. Never again!
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Uses of bisimulation outside of computer science.
@supercooldave: Right. Park invented the name "bisimulation", and didn't seem to be aware of van Benthem's work.
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Au revoir, law of excluded middle?
There seems to be a stage beyond 5, which we might call "Stockholm Syndrome", where you identify so completely with the new, frightening, more complex world that the enemy of complexity, the original simplicity, becomes your enemy: the only interesting groups are noncommutative, the only valid intuitions about formalisms are constructively well-grounded ones. We've all met stage-sixers, haven't we?
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