The Logic seminar is held on Wednesdays at 12-14 in C124. After the seminar we have coffee together at 14-15 in the coffee room on the 4th floor.
The seminar is led by prof. Juha Kontinen and university lecturer Juliette Kennedy.
Schedule of the spring term 2019
Friday 18.1.2019 14-15, B120
Michael Harris: Automorphic Galois representations and the Langlands program
Abstract: Galois representations encode many of the classical questions of number theory. The theory of automorphic forms lies at the border between geometry and analysis on homogeneous spaces,.The Langlands program is predicated on the insight that these two theories mirror each other with astonishing accuracy. This talk will introduce some of the essential questions in the Langlands program and will indicate some recent progress.
Wed 23.1.2019 12-14, C124
no seminar (due to arctic set theory workshop)
Extra seminar: Monday 28.1. 10-12, B119
John T. Baldwin: Strongly minimal Steiner systems: Zilber's conjecture, universal algebra, and combinatorics , Abstract
Wed 30.1.2019 12-14, C124
Andrés Villaveces: Around the Galois group of an AEC
Abstract: I will provide a kind of blueprint for the study of interpretations of Abstract Elementary Classes:
first, I will revisit interpretability and internality in a category-theoretical language (for first order theories, reframing work of Hrushovski and Kamensky in a formalism derived from Makkai). I will then describe the issue of recovering the biintepretability class of a theory in terms of the automorphism group of a saturated model, and the role of the “Small Index Property” (SIP). An SIP theorem for AECs with strong amalgamation properties we published with Ghadernezhad in 2017 is now placed in the context of reconstruction: I propose notions of interpretation between some specific kinds of AECs and explore the role of a Galois group for an AEC.
Wed 6.2.2019 12-14, C124
Jouko Vänäänen: On Shelah's infinitary logic L-one-kappa.
Abstract: Shelah introduced some years ago a new infinitary logic L-one-kappa. We give an alternative formulation and prove that it is equivalent to the original one. Our alternative has some benefits over Shelah's version. In particular, Shelah's logic lacks - in a sense - syntax, while ours has - in a sense - syntax. This is joint work with A. Villaveces and B. Velickovic.
Wed 13.2.2019 12-14, C124
Philip Welch: Closed and Unbounded Classes and the Härtig Quantifier Model
Abstract: We investigate generalisations of the model that arise by enlarging the Gödelian operation of definability to include definability in a language with the "equicardinality quantifier", roughly that the extension of two monadic predicates has the same cardinality in the universe of all sets. Such a model is the Gödel closure of a cub (closed and unbounded) class of ordinals P, which set theorists might write as ( L[P], \in, P ). (The Härtig quantifier model is obtained by taking P = Card - a predicate true of just the cardinal numbers). Under modest strengthenings of the ZFC axioms we can obtain a full picture of what L[Card] must be like. But more than that, we may classify almost all models of the form L[P].
Wed 20.2.2019 12-14, C124
Matti Järvisalo: On the Unexpected Effectiveness of Propositional Satisfiability in Practice
Abstract: In theory, the propositional satisfiability problem (SAT) is NP-complete and no non-brute-force algorithms for it are known. In practice, SAT is a success story of modern computer science. Practical implementations of complete decision procedures for SAT, i.e., SAT solvers, act as "practical NP-oracles" in best practical algorithmic approaches to a wide range of NP and beyond-NP problems, from hardware and software verification to planning and scheduling (and beyond). In this talk, I aim to give a practically-oriented introductory overview of SAT solving, including---as time allows it---a historical perspective and modern algorithmic techniques, connections between SAT solving and propositional proof systems, and how SAT solvers can be employed for solving optimization problems and reasoning problems with (presumable) beyond-NP complexity.
Wed 27.2.2019 12-14, C124
Fausto Barbero: Causal teams
Wed 6.3.2019 12-14, C124
Wed 13.3.2019 12-14, C124
Pietro Galliani: TBA
Wed 20.3.2019 12-14, C124
Jouko Väänänen: TBA
Wed 27.3.2019 12-14, C124
Tabea Rohr (Jena): "Frege's concept of logic reconsidered"
Wed 3.4.2019 12-14, C124
Vera Fischer (Vienna): TBA
Wed 10.4.2019 12-14, C124
Wed 17.4.2019 12-14, C124
Wed 24.4.2019 12-14, C124
Wed 1.5.2019 12-14, C124
Vappu, no seminar
Wed 8.5.2019 12-14, C124