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Logic Seminar

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 Doc. Tapani Hyttinen and university lecturer Juliette Kennedy.

Schedule of the spring term 2018

Wed 17.1.2018 12-14, C124
Yurii Khomskii: Projective maximal independent families

Wed 24.1.2018 12-14, C124
Fan Yang: Deriving and generalizing Arrow’s Theorem in dependence and independence logic

Wed 31.1.2018 12-14, C124
Fan Yang: Deriving and generalizing Arrow’s Theorem in dependence and independence logic, continued

Wed 7.2.2018 12-14, C124
Tim Gendron: Quasicrystals and the Quantum Modular Invariant

Abstract: Hilbert’s 12th problem asks for an explicit description of the Hilbert and ray class fields of a global field $K$. It was inspired by the Theorem of Weber-Fueter, where it is shown that the Hilbert class field of $K$ quadratic and complex over $\mathbb{Q}$ is generated by the modular invariant of any element of $K-\mathbb{Q}$. For $K=\mathbb{Q}(\theta )$ a real quadratic extension of $\mathbb{Q}$ we conjecture that the Hilbert class field is generated by a weighted product of the values of $j^{\rm qt}(\theta)$ where $j^{\rm qt}$ is a discontinuous and multi valued function called the quantum modular invariant. In the case of a real quadratic field of positive characteristic, this conjecture has been verified using the theory of Drinfeld-Hayes modules, wherein the values of $j^{\rm qt}$ are shown to be the modular in invariants of certain ideals in a “small” Dedekind ring. Recently Richard Pink has shown that the same is true in characteristic zero using a quasicrystalline analog of Dedekind ring. We show that the set of quasicrystalline ideals naturally form a Cantor set on which the modular invariant is continuous. We end by considering the new frontier of quasicrystalline algebraic number theory and its prospects for providing a basis for a Drinfeld-Hayes theory in characteristic zero that may eventually allow one to solve Hilbert’s 12th problem for real quadratic extensions of $\mathbb{Q}$.

Wed 14.2.2018 12-14, C124
Fan Yang: Questions and dependency in intuitionistic logic

Wed 21.2.2018 12-14, C124
Fausto Barbero: Interventionist counterfactuals in causal team semantics

Abstract: Teams and multiteams are adequate semantical objects for the discussion of properties of data, such as database dependencies or probabilities. There are instead notions of dependence - such as the causal dependencies arising from manipulationist theories of causation            (Pearl, Woodward) - which cannot be reduced to properties of data. These sorts of dependencies are meaningful in presence of a set of basic causal assumptions - a set of counterfactual statements, which are usually summarized by so-called structural equations.    However, theories of causation make a mixed use of observational and probabilistic notions (which concern data) and of causal notions. I will show how all these forms of reasoning can be modeled within one single semantical framework which simultaneously extends team semantics and structural equation models; and I will analyze some aspects of the logic of interventionist counterfactuals that emerges from this approach. (Joint work with Gabriel Sandu)

Wed 28.2.2018 12-14, C124
Miguel Moreno: \Sigma_1^1-complete quasi-orders in L

Wed 7.3.2018 12-14, C124
exam week

Wed 14.3.2018 12-14, C124
Miikka Vilander: TBA

Wed 21.3.2018 12-14, C124

Wed 28.3.2018 12-14, C124

Wed 4.4.2018 12-14, C124
Easter holiday

Wed 11.4.2018 12-14, C124
Oystein Linnebo TBA

Wed 18.4.2018 12-14, C124
Maria Hämeen-Anttila TBA

Wed 25.4.2018 12-14, C124

Wed 2.5.2018 12-14, C124

Wed 9.5.2018 12-14, C124
exam week


Talks of the fall term 2017

Talks of the spring term 2017

Talks of the fall term 2016

Talks of the spring term 2016

Talks of the fall term 2015

Talks of the spring term 2015

Talks of the fall term 2014

Talks of the spring term 2014

Talks of the fall term 2013

Talks of the spring term 2013

Talks of the fall term 2012

Older talks (2011-2012)


Other seminars

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