Spring Semester

These are the pages of the Logic Seminar at the Università degli Studi di Milano and the Università degli Studi dell'Insubria.

## The Logic Seminar

Welcome to the web pages of the Logic Seminar at the Università degli Studi di Milano and the Università degli Studi dell'Insubria.

The Seminar usually meets every other week during both the autumn and the spring semester, currently on Tuesdays. The exact date, time, and place of each meeting are annonunced on these pages.

There are two types of talks at the Seminar. First, we invite visiting researchers, colleagues, or graduate students to give talks on their own research activity. Second, during each semester we run a proper seminar on a given subject that is of interest to a group of participants. Usually, the participants are not experts on that subject, but wish to learn more about it. The participants then take turns in preparing one- or two-hour talks on a specific topic within the chosen subject.

## Next Talk

**May, 31th 2019**, 11:00, sala riunioni (5th floor), Dipartimento di Informatica, via Celoria 18, Milano

Michele Pra Baldi,

Department of Applied Logic, Philosophy and History of Science, Università di Cagliari
* Płonka Sums in Abstract Algebraic Logic*

In the late 1960’s, the polish mathematician J. Płonka introduced a new class operator, nowadays called Płonka sum, that allowed for a representation theorem for the so-called regular varieties. Recently, Płonka sums have successfully been applied to logic as well.
In this seminar, we outline how an appropriate generalization of Płonka sum can be employed to logical matrices in abstract algebraic logic. It will turn out that the machinery of Płonka sums can be used to provide a complete algebra-based semantics for a wide class of logics. Such class includes logics featuring a variable-inclusion condition among premises and conclusion, and the logic of demodalised analytic implication.