Workshop on Computability Theory 2009


The logic group at Sofia University is organizing an informal workshop on computability theory as a satellite meeting to the Logic Colloquium 2009. The workshop will take place immediately after the end of the Logic Colloquium 2009, on August 6–7 in Sofia. The workshop is planned as a series of lectures given by invited speakers.

Everyone interested in computability theory is invited to extend their stay in Sofia by a couple of days and attend the workshop. There will be no additional registration fee.

People intending to attend the workshop should notify the organizers per email:

Mariya Soskova at or
Alexandra Soskova at


Selected lecturers at the workshop shall be invited to contribute to the special issue of the Journal of Logic and Computation, provisionally titled “Computability at the Logic Colloquium 2009”.

You can find more information about the Logic Colloquium 2009 Proceedings here.


August, 6 (Thursday) August, 7 (Friday)
09:00–10:00 Julia Knight Sergei Goncharov
Describing free groups Turing complexity of models
10:00–10:15 Coffee Break Coffee Break
10:15–11:15 Marat Arslanov Dimiter Skordev and Andreas Weiermann
Definable relations in the n-c.e. degree structures M2-computable real numbers
11:15–11:30 Coffee Break Coffee Break
11:30–12:30 Ivan Soskov Klaus Ambos-Spies
The omega-enumeration degrees Strongly-bounded-Turing degrees of c.e. sets
12:30–14:00 Lunch Lunch
14:00–15:00 Joe Miller Andre Nies and George Barmpalias
Excess complexity and degrees of randomness Ideals in the computably enumerable Turing degrees
15:00–15:15 Coffee Break Coffee Break
15:15–16:15 Iskander Kalimullin Noam Greenberg
Algorithmic reducibilities of algebraic structures Using admissibility for a computable model theory for uncountable structures
16:15–16:30 Coffee Break Coffee Break
16:30–17:30 Hristo Ganchev and Mariya Soskova Antonio Montalban
Coding with K-pairs On complete sets of Pi-n relations of a structure
17:30–17:45 Coffee Break Coffee Break
17:45–18:45 Andy Lewis Charles Harris
Properties of the jump classes Jump Classes of Noncuppable Enumeration Degrees
20:00 Workshop dinner

PDF version of the Schedule