Logic Seminar in Semester I AY 2008/2009

Talks are Wednesday afternoon in Math Studio (S14#03-01)
The general scheme of the seminar is Currently it is planned to start the tutorial at 15:00 hrs and the talk at 16:00 hrs. On days where there is a Colloquium Talk, both the tutorial and the seminar talk might start later. The schedule is as follows.
  1. 13/08/2008, Week 1
    16.00 hrs: Organizational Meeting.

  2. 20/08/2008, Week 2
    15.00 hrs: Johanna Franklin. Tutorial Reverse Mathematics.
    16.00 hrs: Yang Yue. Talk High Minimal Pairs in Enumeration Degrees.
    Abstract of talk: I will talk about a recent joint work with Guohua Wu and Andrea Sorbi. We showed the existence of high minimal pairs in e-degrees. Motivations and some technical point will be explained in my talk.

  3. 27/08/2008, Week 3
    15.00 hrs: Johanna Franklin. Tutorial Reverse Mathematics.
    16.00 hrs: Wang Wei. Talk Uncountable Embeddings into the Turing Degrees.
    Abstract of talk: I will present a proof that under MA each locally countable upper semi-lattice of size the continuum can be embedded into Turing degrees. Relating history and difficulties in solving similar questions will also be addressed.

  4. 03/09/2008, Week 4
    No talk, ALC 2008 in Kobe.

  5. 10/09/2008, Week 5
    15.00 hrs: Johanna Franklin. Tutorial Reverse Mathematics.
    16.00 hrs: Frank Stephan. Talk Numberings Optimal for Learning.
    Abstract of talk: This talk extends previous studies on learnability in non-acceptable numberings by considering the question: for which criteria which numberings are optimal, that is, for which numberings it holds that one can learn every learnable class using the given numbering as hypothesis space. Furthermore an effective version of optimality is studied as well. It is shown that the effectively optimal numberings for finite learning are just the acceptable numberings. In contrast to this, there are non-acceptable numberings which are optimal for finite learning and effectively optimal for explanatory, vacillatory and behaviourally correct learning. The numberings effectively optimal for explanatory learning are the K-acceptable numberings. A similar characterization is obtained for the numberings which are effectively optimal for vacillatory learning. Furthermore, it is studied which numberings are optimal for one and not for another criterion: among the criteria of finite, explanatory, vacillatory and behaviourally correct learning all separations can be obtained; however every numbering which is optimal for explanatory learning is also optimal for consistent learning.

  6. 17/09/2008, Week 6
    15.00 hrs: Johanna Franklin. Tutorial Reverse Mathematics.
    16.00 hrs: Wu Liuzhen.

  7. 01/10/2008, Week 7
    No talk, Hari Raya Puasa.

  8. 08/10/2008, Week 8
    15.00 hrs: Wu Guohua. Tutorial Intermediate Degrees.
    16.00 hrs: Liu Jiang.

  9. 15/10/2008, Week 9
    15.00 hrs: Wu Guohua. Tutorial Intermediate Degrees.
    16.00 hrs: Li Yanfang.

  10. 22/10/2008, Week 10
    15.00 hrs: Pavel Semukhin. Tutorial Automatic Structures.
    16.00 hrs: Shen Demin.

  11. 29/10/2008, Week 11
    15.00 hrs: Pavel Semukhin. Tutorial Automatic Structures.
    16.00 hrs: Yang Sen.

  12. 05/11/2008, Week 12
    15.00 hrs: Pavel Semukhin. Tutorial Automatic Structures.
    16.00 hrs: Zhu Huiling.

  13. 12/11/2008, Week 13
    15.00 hrs: Pavel Semukhin. Tutorial Automatic Structures.
    16.00 hrs: Johanna Franklin.
Talks from the last semester.