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ILLC-Day in Bonn
Mathematisches Institut, Bonn
November 30, 2003

A Cooperative Effort of the Group LOGIC in BONN (LiB) and the Institute for Logic, Language and Computation (ILLC).
Organizer: Benedikt Löwe
Date: November 30, 2003
Location: Hausdorff-Raum, Beringstraße 3

The ILLC-Day in Bonn will be the second part of a pair of one-day workshops connecting logical research in Bonn and at the ILLC in Amsterdam. The first event was the LiB-Day in Amsterdam (June 30, 2003). We hope that several researchers from the Bonn Forschergruppe Wissensformate will be present for discussions.

All researchers, graduate students and undergraduate students are cordially invited to join us for the talks.

For further information, feel free to contact Benedikt Löwe.

1130-1220 Yde Venema (ILLC, Amsterdam) The algebraic side of modal logic: recent developments
1220-1400 LUNCH BREAK
1400-1450 Thomas Müller (PhilS-LFBIII, Bonn) Probabilities in branching space-times
1455-1545 Nick Bezhanishvili (ILLC, Amsterdam) Extensions of S52 and better-quasi-orderings
1545-1615 COFFEE BREAK
1615-1705 Dick de Jongh (ILLC, Amsterdam) Intuitionistic propositional calculus: results of the last decade
1710-1800 Michiel van Lambalgen (ILLC, Amsterdam) Time: from cognition to language

Note that Robert van Rooy will give a general talk on Exhaustive Interpretation: Why and How as part of the lecture series colloquium logicum Universität Bonn the following day: December 1st, 14-16 in the Großer Übungsraum of the Philosophisches Seminar. This talk continues the series of Amsterdam talks in Bonn.

ILLC-Day is funded by the Beauftragter für die Pflege und Förderung der Beziehungen zwischen den Hochschulen des Landes Nordrhein-Westfalen, des Königreichs der Niederlande, des Königreichs Belgien und des Großherzogtums Luxemburg ("Benelux-Beauftragter NRW"), the Philosophische Fakultät der Rheinische Friedrich-Wilhelms Universität Bonn, the Rheinische Friedrich-Wilhelms-Universität Bonn, and the Bonn International Graduate School Mathematics, Physics, Astronomy BIGS-MPA.


Yde Venema: The algebraic side of modal logic: recent developments

Modal logics have algebraic manifestations in the form of certain classes of so-called Boolean algebras with operators (BAOs). Recent years have witnessed an increase of activity in this area, and the aim of this talk is to survey some of these developments.

More in particular, the talk will center around various notions of canonicity; this concept concerns the question, which properties are preserved when we move from an arbitrary BAO to a completion, that is, a complete superalgebra of the original one. The notion of canoniciy, which on the logical side plays an important role in modal completeness proofs, has recently revealed some of its secrets. In particular, an open problem raised by Kit Fine in the seventies has been solved just a few months ago.

Thomas Müller: Probabilities in branching space-times

How do probabilities mesh with the causal structure of space-time?

Probabilities are about chance set-ups such as the tossing of a coin. These set-ups are located spatially and temporally. Thus, it is to be expected that in some circumstances, chance set-ups "here-now" can have an influence on chance set-ups "then-there". Probability theory of itself has nothing to say on this matter. However, the theory of branching space-times (Belnap, Synthese 92, 1992) provides a framework within which causal dependencies among chance set-ups may be described.

In my talk, I will first sketch Belnap's theory of branching space-times, including his account of "originating causes". In the second part of my talk, I will introduce a general theory of probabilities for branching space-times.

Dick de Jongh: Intuitionistic propositional calculus: results of the last decade

Results of Rybakov, Pitts, Ghilardi, Iemhoff will be discussed and their relation to work done by the speaker in cooperation with Visser and with Bezhanishvili.

Michiel van Lambalgen: Time: from cognition to language

It is not immediately clear why human beings would experience time at all. Many skills do not require explicit representations of temporal succession or duration. There exists some psychological evidence, however, that conscious awareness of time comes with the capacity for planning. E.g., children's ability to use temporal expressions seems to covary with their ability to recognize plans; and planning deficits covary with temporal disintegration. If planning is an important determinant of our sense of time, one might expect that the representation of time in language, as tense and aspect, shows traces of its origin in planning. Fortunately, this idea is testable, since planning can be formalized logically, on the basis of logic programming with negation as failure. We will sketch the resulting semantics, and show what it predicts for tense and aspect.

Last changed: November 27th, 2003