For more information about this meeting, contact Stephen Simpson.

Title: | The strength of Ramsey's Theorem for Pairs |

Seminar: | Logic Seminar |

Speaker: | Chi-Tat Chong, National University of Singapore |

Abstract Link: | http:// |

Abstract: |

Ramseys's Theorem for Pairs (RT^2_2) states that every coloring
of pairs of numbers into two colors (red or blue) has an infinite
homogeneous set A, i.e. pairs of numbers from A all share the same color.
A seemingly weaker version of RT^2_2, the Stable Ramsey's Theorem for
Pairs, states that the same conclusion holds for coloring of pairs with the
additional property that all pairs of numbers with the same first
co-ordinate are eventually all red or blue. In this talk we sketch a
proof of a recent result that over the base theory RCA_0, SRT^2_2 is
strictly weaker than RT^2_2, solving an open problem in reverse
mathematics. This is joint work with Ted Slaman and Yue Yang. |

### Room Reservation Information

Room Number: | MB106 |

Date: | 06 / 11 / 2012 |

Time: | 10:00am - 11:15am |