Friday, 6 March 2015 | |
14:00 - 14:30 | Check in |
14:30 - 15:15 | C. T. Chong (National Univ. of Singapore) |
Title : The coding LemmaAbstract
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Coffee Break | |
15:45 - 16:30 | Emanuele Frittaion (Tohoku University) |
Title : Combinatorial principles via a partition theorem for pairs of rational numbersAbstractI will discuss the reverse mathematics and computability theory of the following extension of RT22 (Ramsey's theorem for pairs of natural numbers and two colors): Theorem [Erd\"{o}s, Rado 1952] The partition relation Q \to (\aleph_0, Q)^2 holds. The theorem says that that for every 2-coloring f: [Q]^2\to 2 of pairs of rational numbers there exists either an infinite 0-homogeneous set or a dense 1-homogeneous set. More explicitly, there exists an infinite set A \subseteq Q such that either f\restriction [A]^2=0 or (A, \leq_Q) is dense and f\restriction [A]^2=1. I will also talk about analogs of CAC (Chain Anti-Chain) and ADS (Ascending Descending Sequence) related to Q \to (\aleph_0, Q)^2. |
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16:45 - 17:30 | Hiroshi Sakai (Kobe University) |
Title : On monadic second order theory of $\omega_2$Abstract
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