The number of logic and philosophy seminars has grown exponentially during these Coronavirus times of ours. I am listing here some of the meetings that compete for our time and disposition with the 'Working Logician'.
There is the Logicians in Quarantine, organized by the
Brazilian Logic Society / Logic Interest Group/Brazilian Computing Society
website at http://sbl.org.br/pmwiki.php/LQ/Quarentena.
The Proof Society Seminar https://www.proofsociety.org/proof-theory-seminar/slides.html
The SuperGroup Logic Seminar https://sites.google.com/view/logicsupergroup/the-logic-supergroup
The Buenos Aires logic group calls its seminar Seminario de Lógica Iberoamericana (SeLoI), https://ba-logic.com/seloi/
There are many other seminar series, but the point of this post is to list the talks in thee PUC-Rio seminar, organized by Luiz Carlos Pereira as real working seminars for his students. In reverse cronological order the meetings last semester were:
16/12/2020 Title: Trying to understand resource consciousness
Prof. Elaine Pimentel DMAT/UFRNAbstract: We look at substructural calculi from a game semantic point of view, guided by certain intuitions about resource conscious and, more specifically, cost conscious reasoning. To this aim, we start with a game, where player I defends a claim corresponding to a (single-conclusion) sequent, while player II tries to refute that claim. Branching rules for additive connectives are modeled by choices of II, while branching for multiplicative connectives leads to splitting the game into parallel subgames, all of which have to be won by player I to succeed. The game comes into full swing by adding cost labels to assumptions, and a corresponding budget. Different proofs of the same end-sequent are interpreted as more or less expensive strategies for I to defend the corresponding claim. This leads to a new kind of labelled calculus, which can be seen as a fragment of SELL (subexponential linear logic). Finally, we generalize the concept of costs in proofs by using a semiring structure, illustrate our interpretation by examples and investigate some proof-theoretical properties.
The talk assumes *no prior knowledge* on games or substructural logic. Only a basic notion of sequent systems is advisable.
This is a joint work with Timo Lang, Carlos Olarte and Christian G. Fermüller.
December 09, 2020 TITLE. A Constructivist Reading of the Epsilon Calculus
SPEAKERS. Mattia Petrolo (
ABSTRACT. The aim of this
constructive aspects of this
in the general proof
Thus, in the second part of
displayed via the epsilon
Extra, as it happened in Prof Giorgio Venturi's seminar series 1/12/2020 Title:
A universal graph-theoretic criterion for relevance
Prof Peter Verdée
Abstract
In this talk I present work in progress by my FNRS MIS funded research team (Pilar Terres, Pierre Saint-Germier, Joao Daniel Dantas) working on explanatory inference. We came up with a criterion for relevance of the entailment relation, relative to a given logic. One of the weak criteria of relevance presented in the literature is the principle of variable sharing: if a (multiple conclusion) sequent is relevantly valid then every formula in the sequent needs to have at least one variable in common with the other formulas in the sequent. I present a couple of cases from which it should be clear that this criterion (while being necessary) certainly is not sufficient for relevance. We solve these problems by analyzing relevance in terms of connectivity. The idea is to say that a sequent is relevantly valid iff a connected graph (of a specific nature) can be established that contains all of the formulas of the sequent. The basis of this idea is the concept of a constitution of a logic. This is a set of sequents that express full logical grounds of all formulas of the language of the logic (the grounded formula of each sequent is underlined, the non-underlined formulas are the partial grounds--examples are "A,B>A&B", "A&B>A" and "A, A->B > B" in the case of classical logic). The partial grounds (the non-underlined formulas) of each formula determine the way in which formulas of the potentially relevant sequents can be connected to other formulas of the sequent. We will present and motivate the criterion, give a couple of examples, and present some graph-theoretical results concerning this criterion.
02/12/2020 The pragmatic structure of mathematics
26 y 27 november 2020 Title: A maximalist view on the meaning of logical connectives
Profa. Pilar Terrés
25/11/2020 Title: The BA plan: how to recapture classicality in the ST-hierarchy
18/11/20: Reflective Equilibrium and Logical Pluralism
The aim of this talk is to propose a pluralist view of logic that
makes possible a peaceful coexistence between classical logic and some
paraconsistent and paracomplete logics. The central point is to
understand the inference rules of classical, intuitionistic, Nelson's
N3, Belnap-Dunn 4-valued logic, and BLE (the basic logic of evidence)
as a result of two ingredients: i. inferential practices based, in
each case, on a fundamental semantic notion; ii. reflective
equilibrium. The result of combining logical pluralism with reflective
equilibrium is a weak form of revisionism, according to which logic is
not really revised. The idea is rather that different formal systems
are concerned with different properties of propositions, and therefore
are appropriate to different contexts of reasoning. (Joint work with
Marcos Silva)
4/11/20: Hermann II
28/10/20: Título: Redundancy in huge Natural Deduction proofs or how to obtain polynomial certificates for Non-Hamiltonian graphs.
30 set 2020 10:30 AM São Paulo: Veloso-type Solutions to Metapuzzles
Prof. Frank Thomas SautterAbstract. I introduce a method for solving metapuzzles inspired by
Paulo Veloso's General Theory of Problems. This method is not the
most efficient one, but its virtues include faithful modeling of the
flow of information and logical standardization through the use of the
same first-order predicates in all its applications.
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professor Diogo H.B. Dias (DF/UENP & DF/USP): Abstract: The aim of this talk is to investigate some arguments for logical monism, and to show how, with minor modifications, these arguments could be used to defend the adequacy of different logics. Hence, as a defense of logical monism, they all fail. From this analysis, we'll present a different kind of pluralism, based on the notion that logic is relative to its domain of application. |
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