For more information about this meeting, contact Stephen Simpson, Jan Reimann.

Title: | Pi^1_1-conservative extensions of subsystems of second-order arithmetic. |

Seminar: | Logic Seminar |

Speaker: | Keita Yokoyama, Tokyo Institute of Technology |

Abstract: |

For the study of reverse mathematics, (Pi^1_1-)conservation results
between two different systems are very important. Many important
theorems are well-known, e.g., WKL_0 and RCA_0^+ are
Pi^1_1-conservative extensions of RCA_0. Moreover, we can show the
following: for given a Pi^1_2-theory T, there exists a maximal
Pi^1_2-theory which is Pi^1_1-conservative over T. Then, what is the
maximal extension of RCA_0, ACA_0, etc. in this sense? In this talk, I
will give a survey on this topic including Henry Towsner's resent
results. |

### Room Reservation Information

Room Number: | MB315 |

Date: | 03 / 12 / 2013 |

Time: | 02:30pm - 03:45pm |