Join the Logica Universalis Webinar 2022!

The Logica Universalis Webinar is a World Seminar Series connected to the journal Logica Universalis, the book series Studies in Universal Logic and the Universal Logic Project. It is an open platform for all scholars interested in the many aspects of logic. The project started in 2021. Click here to access last year's webinar website.

The LUW 2022 series started with an "extraordinary" session:
LUA celebration of the fourth World Logic Day: Roundtable on "The Exceptionality of Logic", Jan 14, 2022. See here fore more information.

The sessions take place on Wednesdays at 4pm CET. They are held via Zoom through the platform Cassyni and are free to attend. Please register and subscribe in advance.
Registration is now open!

Please note that you will be required to register before subscribing to the webinar series. You will be automatically directed to the registration page or click here


Video recordings of the seminars are uploaded on the YouTube channel Universal Logic Project until the end of this year 2022 and on the Cassyni platform, which will continue also in the future.

Each session of the webinar is chaired by a member of the editorial board of the journal Logica Universalis (LU), the book series Studies in Universal Logic (SUL) or an organizer of an event of the Universal Logic Project (ULP). Sessions will start with a short presentation of a logical organization related to the region of the speaker or the topic of the talk. The talk (30 min) will focus on a recently published paper in LU, on a book in SUL, on an event or on the ULP. Talks are followed by a discussion (15 min).

Webinar Schedule

Date

Speaker

Title

Organization

Chair

February 9                          

Antonino Drago (University “Federico II” of Naples, Italy)

An Intuitionist Reasoning Upon Formal Intuitionist Logic: Logical Analysis of Kolmogorov’s 1932 Paper

Italian Society of Logic and Philosophy of Science (SILFS),
Vincenzo Fano, president

Francesco Paoli, Editorial Board  SUL

February 16

Alexandre Costa-Leite (University of Brasília, Brazil),
Edelcio G. de Souza (University of São Paulo, Brazil)
and 
Diogo H. B. Dias (State University of Northern Paraná, Jacarezinho, Brazil)  

Paraconsistent Orbits of Logics

Logic in the Plane (Lógica no Avião),
Rodrigo Freire, president

Itala D'Ottaviano, Editorial Board LU                                                                                   

March 9

Jean-Yves Beziau (Federal University of Rio de Janeiro, Brazil) 

The 2nd World Logic Prizes Contest

Logica Universalis Association,
Katarzyna Gan-Krzywoszyńska, secretary

Göran Sundholm,

President of the Jury of the 1st World Logic Prizes Contest

March 16

Eunsuk Yang (Jeonbuk National University, South Korea)

Implicational Tonoid Logics and Implicational Partial Galois Logics  Korean Association of Logic,
Ilho Park, Secretary
Jui-Lin Lee, Editorial Board SUL

April 13

Andrew Schumann (University of Information Technology and Management in Rzeszow, Poland)

On the Origin of Logical Determinism in Babylonia Warsaw Scientific Society,
Jan Woleński
Jean-Yves Beziau

Editor-in-Chief Logica Universalis

April 20

Nate Ackermann (Harvard University, USA) Encoding Complete Metric Structures by Classical Structures Cambridge/Boston Logic Group,
Rehana Patel
Andrei Rodin

Editorial Board LU

May 11

Alexei Muravitsky (Louisiana Scholars’ College, Northwestern State University, USA) On Nonmonotonic Consequence Relations Moscow Logic School,
Alex Citkin
Melvin Fitting, Editorial Board SUL

May 18

Roland Bolz, (Humboldt University, Berlin, Germany) Logical Diagrams, Visualization Criteria and Boolean Algebras

(Chapter of the book The Exoteric Square of Opposition)

Organizers of the 7th SQUARE,
Hans SmessaertDany Jaspers and Lorenz Demey
Ioannis Vandoulakis, Vice-President of LUA (Logica Universalis Asssociaton) and co-editor of the book The Exoteric Square of Opposition

June 8

Ciro Russo (Federal University of Bahia, Salvador, Brazil)

Winner of the 2nd World Logic Prizes Contest

 Coproduct and Amalgamation of Deductive Systems by Means of Ordered Algebras Logica Universalis Organization, presented by its President Jean-Yves Beziau, Founder and Organizer of the World Logic Prizes Contest

Ivan Varzinczak, Editorial Board LU and President of  the 2nd Word Logic Prizes Contest

June 15

Anne-Françoise Schmid (Ecole des Mines, Paris, France) The Place and Value of Logic in Louis Couturat’s Philosophical Thinking
(Collected in the book Logic in Question - Talks from the Annual Sorbonne Logic Workshop (2011- 2019))

Organizers of the workshop Logic in Question and editors of the book Logic in Question - Talks from the Annual Sorbonne Logic Workshop (2011- 2019),
Jean-Yves Beziau, Jean-Pierre Desclés, Amirouche Moktefi, Anca Christine Pascu

Razvan Diaconescu, Editorial Board SUL

July 6

Stepan I. Bashmakov (Siberian Federal University, Krasnoyarsk, Russia) Unification in Pretabular Extensions of S4 Siberian Logic Group,
Nikolay Bazhenov


Vladimir Vasyukov, Editorial Board SUL

July 14

Mateusz Klonowski (Nicolaus Copernicus University in Toruń, Poland) Axiomatization of Some Basic and Modal Boolean Connexive Logics

Toruń Logic Group,
Jacek Malinowski

Raja Natarajan,
Editorial Board LU

August 3

Norihiro Kamide (Teikyo University, Japan)

An Extended Paradefinite Logic Combining Conflation, Paraconsistent Negation, Classical Negation, and Classical Implication: How to Construct Nice Gentzen-type Sequent Calculi

TBA

Arnon Avron,
Editorial Board LU

August 10

Kenji Tokuo (National Institute of Technology, Japan) Natural Deduction for Quantum Logic

International Quantum Structures Association - IQSA,
Christian de Ronde

Francesco Paoli,
Editorial Board SUL

September 7

David Makinson Frege’s Ontological Diagram Completed

Australasian Association of Logic,
presented by its president Guillermo Badia

Valentin Goranko,
Editorial Board LU
September 28 Tin Adlešic (University of Zagreb, Croatia) A Modern Rigorous Approach to Stratification in NF/NFU European Set Theory Society,
presented by its president Philip Welch
Srecko Kovac,
Editorial Board LU

Speakers and Abstracts

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February 9, 2022 – Antonino Drago
An Intuitionist Reasoning Upon Formal Intuitionist Logic: Logical Analysis of Kolmogorov’s 1932 Paper     

Chair: Francesco Paoli
Editorial Board SUL

Associate Organization: Italian Society of Logic and Philosophy of Science (SILFS),
presented by its president Vincenzo Fano

Two dichotomies are considered as the foundations of a scientific theory: the kind of infinity—either potential or actual-, and the kind of organization of the theory—axiomatic or problem-based. The original intuitionist program relied on the choices of potential infinity and the problem-based organization. I show that the logical theory of Kolmogorov’s 1932 paper relied on the same choices. A comparison of all other theories sharing the same foundational choices allows us to characterize their common theoretical development through a few logical steps. The theory illustrated by Kolmogorov’s paper is then rationally re-constructed according to the steps of this kind of development. One obtains a new foundation of intuitionist logic, which is of a structural kind since it is based on and developed according to the structure of the above mentioned two fundamental choices. In addition, Kolmogorov’s illustration of his theory of intuitionist logic is an instance of rigorous reasoning of the intuitionist kind.

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February 16, 2022 – Alexandre Costa-LeiteEdelcio G. de Souza and Diogo H. B. Dias – Paraconsistent Orbits of Logics

Chair: Itala D'Ottaviano  
Editorial Board LU

Associate Organization: Logic in the Plane (Lógica no Avião),
presented by its president Rodrigo Freire

Some strategies to turn any logic into a paraconsistent system are examined. In the environment of universal logic, we show how to paraconsistentize logics at the abstract level using a transformation in the class of all abstract logics called paraconsistentization by consistent sets . Moreover, by means of the notions of paradeduction and paraconsequence we go on applying the process of changing a logic converting it into a paraconsistent system. We also examine how this transformation can be performed using multideductive abstract logics. To conclude, the conceptual notion paraconsistent orbit of a logic is proposed.

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March 9, 2022 – Jean-Yves Beziau
The 2nd World Logic Prizes Contest

Chair: Göran Sundholm,
President of the Jury of the 1st World Logic Prizes Contest
Associate Organization: Logica Universalis Association,
presented by its secretary Katarzyna Gan-Krzywoszyńska

We discuss the development of the logic prizes and we present the 2nd World Logic Prizes Contest, that will take place in Crete in April 2022 during the 7th UNILOG  (World Congress and School on Universal Logic)

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March 16, 2022 – Eunsuk Yang – Implicational Tonoid Logics and Implicational Partial Galois Logics

Chair: Jui-Lin Lee
Editorial Board SUL 

Associate Organization: Korean Association of Logic,
presented by its Secretary Ilho Park

This paper combines two classes of generalized logics, one of which is the class of weakly implicative logics introduced by Cintula and the other of which is the class of gaggle logics introduced by Dunn. For this purpose we introduce implicational tonoid logics. More precisely, we first define implicational tonoid logics in general and examine their relation to weakly implicative logics. We then provide algebraic semantics for implicational tonoid logics. Finally, we consider relational semantics, called Routley–Meyer–style semantics, for finitary those logics.

Implicational tonoid logics and their relational semantics have been introduced by Yang and Dunn. This paper extends this investigation to implicational partial Galois logics. For this, we first define some implicational partial gaggle logics as special kinds of implicational tonoid logics called “implicational partial Galois logics.” Next, we provide Routley–Meyer-style relational semantics for finitary those logics.

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April 13, 2022 – Andrew Schumann (Head of the Department of Cognitive Science and Mathematical Modeling, University of Information Technology and Management in Rzeszow, Poland) –  On the Origin of Logical Determinism in Babylonia

Chair: Jean-Yves Beziau
Editor-in-Chief Logica Universalis

Associate Organization: Warsaw Scientific Society,
presented by Jan Woleński

In this paper, I show that the idea of logical determinism can be traced back from the Old Babylonian period at least. According to this idea, there are some signs (omens) which can explain the appearance of all events. These omens demonstrate the will of gods and their power realized through natural forces. As a result, each event either necessarily appears or necessarily disappears. This idea can be examined as the first version of eternalism – the philosophical belief that each temporal event (including past and future events) is actual. In divination lists in Akkadian presented as codes we can reconstruct Boolean matrices showing that the Babylonians used some logical-algebraic structures in their reasoning. The idea of logical contingency was introduced within a new mood of thinking presented by the Greek prose – historical as well as philosophical narrations. In the Jewish genre ’aggādōt, the logical determinism is supposed to be in opposition to the Greek prose.

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April 20, 2022 – Nate Ackermann (Harvard University, USA) – Encoding Complete Metric Structures by Classical Structures

Chair: Andrei Rodin
Editorial Board LU

Associate Organization: Cambridge/Boston Logic Group, 
presented by Rehana Patel

We show how to encode, by classical structures, both the objects and the morphisms of the category of complete metric spaces and uniformly continuous maps. The result is a category of, what we call, cognate metric spaces and cognate maps. We show this category relativizes to all models of set theory (unlike the category of complete metric spaces and uniformly continuous maps). We extend this encoding to an encoding of complete metric structures by classical structures. This provide us with a general technique for translating results about infinitary logic on classical structures to the setting of infinitary continuous logic on continuous structures. Our encoding will also allow us to talk about not only the relations between complete metric structures, but also the potential relations between complete metric structures, i.e. those which are satisfied in some larger model of set theory. For example we will show that given any two complete metric structures we can determine if they are potentially isomorphic by looking at any admissible set which contains them both.

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May 11, 2022 – Alexei Muravitsky (Louisiana Scholars’ College, Northwestern State University, USA) –  On Nonmonotonic Consequence Relations

Chair: Melvin Fitting
Editorial Board LU

Associate Organization: Moscow Logic School,
presented by  Alex Citkin

We discuss nonmonotonic reasoning in terms of consequence relations and corresponding operators. Based on the matrix consequence that gives the monotonic case, we define a restricted matrix consequence that illustrates the nonmonotonic case. The latter is a generalization of the relation of logical friendliness introduced by D. Makinson. We prove that any restricted single matrix consequence, although it may be nonmonotonic, is always weakly monotonic and, in the case of a finite matrix, the restricted matrix consequence is very strongly finitary. Further, by modifying the definition of logical friendliness relation formulated specifically in a proof-theoretic manner, we show a possibility of obtaining other reflexive nonmonotonic consequence relations, for which a limited result towards finitariness is proved. This leads to numerous questions about nonmonotonic consequence relations in the segment between the monotonic consequence relation based on intuitionistic propositional logic and logical friendliness.

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May 18, 2022 – Roland Bolz (Humboldt University, Berlin, Germany) – Visualization Criteria and Boolean Algebras (Chapter of the book The Exoteric Square of Opposition)

Chair: Ioannis Vandoulakis,
Vice-President of LUA (Logica Universalis Asssociaton) and co-editor of the book The Exoteric Square of Opposition

Associate Organization: Organizers of the 7th SQUARE,
Hans SmessaertDany Jaspers and Lorenz Demey

This paper presents logical diagrams as attempts to visualize facts about logical/linguistic/conceptual systems. It introduces four criteria for assessing visualization: 1) completeness, 2) correctness, 3) lack of distortion, and 4) legibility. It then studies presents well-known families of diagrams, based on the geometrical figures of a) the hexagon, and b) the tetrakis hexahedron. These are usually presented as exemplary diagrams. To understand better why they succeed so well at visualizing logical information, they are presented as visualizations of complete (finite) Boolean algebras. This also establishes the connection between the combinatorial concept of partition and the logical concept of opposition (i.e. contradiction, contrariness, and subcontrariness). Finally, the paper suggests that the two geometrical figures in question are part of a larger family of polytopes with deep connections to Boolean algebras.

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June 8, 2022 – Ciro Russo (Federal University of Bahia, Salvador, Brazil) – Coproduct and Amalgamation of Deductive Systems by Means of Ordered Algebras

Chair: Ivan Varzinczak,
Editorial Board LU and President of  the 2nd Word Logic Prizes Contest

Associate Organization: Logica Universalis Organization,
presented by its President Jean-Yves Beziau, Founder and Organizer of the World Logic Prizes Contest

We propose various methods for combining or amalgamating propositional languages and deductive systems. We make heavy use of quantales and quantale modules in the wake of previous works by the present and other authors. We also describe quite extensively the relationships among the algebraic and order-theoretic constructions and the corresponding ones based on a purely logical approach.

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June 15, 2022 – Anne-Françoise Schmid (Ecole des Mines, Paris, France) – The Place and Value of Logic in Louis Couturat’s Philosophical Thinking (Collected in the book Logic in Question - Talks from the Annual Sorbonne Logic Workshop (2011- 2019))

Chair: Razvan Diaconescu,
Editorial Board SUL

Associate Organization: Organizers of the workshop Logic in Question and editors of the book Logic in Question - Talks from the Annual Sorbonne Logic Workshop (2011- 2019),
Jean-Yves Beziau, Jean-Pierre Desclés, Amirouche Moktefi, Anca Christine Pascu

Louis Couturat is known for affirming and defending the works of logic available during his lifetime, especially those of Russell and the Italian school. His work of conceptual analysis is exceptional and unique in its ability to put in relation the mathematicians of his time, for which his reputation is well deserved. Taking a closer look at his work at large, the place and value of logic are not simple problems for Couturat. On one hand, the new logic differs from the Greek methods of Aristotelian logic, and yet it has no place in mathematics unlike the algebraic school Couturat frequently addresses. On the other hand, he discovers the logic of Russell as a novelty and invention, to which he gives, in agreement with Lalande and Itelson, the old name of Logistics. He complicates things further in his unpublished Manuel de Logistique (written in 1905), where he presents it as an ancient science to which symbols have been added (however, we know he does not like the use of symbols as Peano instituted). Couturat is therefore in a complex relationship with the logic of his time. The following is an attempt to unfold the consequences. Our main source for this lecture  on Louis Couturat will be the correspondences with Bertrand Russell between 1897 and 1913, edited and annotated by us. It is all the more  valuable because we have letters from both contributors and it is the most important scientific correspondence of Russell.

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Stepan I. Bashmakov

July 6, 2022 – Stepan I. Bashmakov (Siberian Federal University, Krasnoyarsk, Russia) – Unification in Pretabular Extensions of S4

Chair: Vladimir Vasyukov,
Editorial Board SUL

Associate Organization: Siberian Logic Group,
presented by Nikolay Bazhenov

L.L. Maksimova and L. Esakia, V. Meskhi showed that the modal logic S4 has exactly 5 pretabular extensions PM1–PM5. In this paper, we study the problem of unification for all given logics. We showed that PM2 and PM3 have finitary, and PM1, PM4, PM5 have unitary types of unification. Complete sets of unifiers in logics are described.

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Mateusz Klonowski

July 14, 2022 – Mateusz Klonowski (Nicolaus Copernicus University in Toruń, Poland) – Axiomatization of Some Basic and Modal Boolean Connexive Logics

Chair: Raja Natarajan,
Editorial Board LU

Associate Organization: Toruń Logic Group,
presented by Jacek Malinowski

Boolean connexive logic is an extension of Boolean logic that is closed under Modus Ponens and contains Aristotle’s and Boethius’ theses. According to these theses (i) a sentence cannot imply its negation and the negation of a sentence cannot imply the sentence; and (ii) if the antecedent implies the consequent, then the antecedent cannot imply the negation of the consequent and if the antecedent implies the negation of the consequent, then the antecedent cannot imply the consequent. Such a logic was first introduced by Jarmużek and Malinowski, by means of so-called relating semantics and tableau systems. Subsequently its modal extension was determined by means of the combination of possible-worlds semantics and relating semantics. In the following article we present axiomatic systems of some basic and modal Boolean connexive logics. Proofs of completeness will be carried out using canonical models defined with respect to maximal consistent sets.

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August 3, 2022 – Norihiro Kamide (Teikyo University, Japan) – An Extended Paradefinite Logic Combining Conflation, Paraconsistent Negation, Classical Negation, and Classical Implication: How to Construct Nice Gentzen-type Sequent Calculi

Chair: Arnon Avron,
Editorial Board LU

Associate Organization: TBA,
presented by 

In this study, an extended paradefinite logic with classical negation (EPLC), which has the connectives of conflation, paraconsistent negation, classical negation, and classical implication, is introduced as a Gentzen-type sequent calculus. The logic EPLC is regarded as a modification of Arieli, Avron, and Zamansky’s ideal four-valued paradefinite logic (4CC) and as an extension of De and Omori’s extended Belnap–Dunn logic with classical negation (BD+) and Avron’s self-extensional four-valued paradefinite logic (SE4). The completeness, cut-elimination, and decidability theorems for EPLC are proved and EPLC is shown to be embeddable into classical logic. The strong equivalence substitution property and the admissibilities of the rules of negative symmetry, contraposition, and involution are shown for EPLC. Some alternative simple Gentzen-type sequent calculi, which are theorem-equivalent to EPLC, are obtained via these characteristic properties.

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August 10, 2022 – Kenji Tokuo (National Institute of Technology, Japan) – Natural Deduction for Quantum Logic

Chair: Francesco Paoli,
Editorial Board SUL

Associate Organization: International Quantum Structures Association - IQSA,
presented by Christian de Ronde

This paper presents a natural deduction system for orthomodular quantum logic. The system is shown to be provably equivalent to Nishimura’s quantum sequent calculus. Through the Curry-Howard isomorphism, quantum l-calculus is also introduced for which strong normalization property is established.

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David Makinson

September 7, 2022 – David Makinson – Frege’s Ontological Diagram Completed

Chair: Valentin Goranko,
Editorial Board LU

Associate Organization: Australasian Association of Logic,
presented by its president Guillermo Badia

In a letter of 1891, Frege drew a diagram to illustrate his logical ontology. We observe that it omits features that play an important role in his thought on the matter, propose an extension of the diagram to include them, and compare with a diagram of the ontology of current first-order logic.

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tin-adlesic

September 28, 2022 – Tin Adlešic – A Modern Rigorous Approach to Stratification in NF/NFU

Chair: Srecko Kovac,
Editorial Board LU

Associate Organization: European Set Theory Society,
presented by its president Philip Welch

:  The main feature of NF/NFU is the notion of stratification, which sets it apart from other set theories. We define stratification and prove constructively that every stratified formula has the (unique) least assignment of types. The basic notion of stratification is concerned only with variables, but we extend it to abstraction terms in order to simplify further development. We reflect on nested abstraction terms, proving that they get the expected types. These extensions enable us to check whether some complex formula is stratified without rewriting it in the basic language. We also introduce natural numbers and a variant of the axiom of infinity, in order to precisely introduce type level ordered pairs, which are crucial in simplifying the definitions in the last part of the article. Using these notions we can easily define the sets of ordinal and cardinal numbers, which we show at the end of the article. The same approach can be readily applied to NF.