Events

A Logic Day in Bochum

With the visits of Roberto Giuntini and Bernhard Weiss, we will have a special Logic Day workshop at RUB. 

Date & Venue

Program

10:30 to 11:30: Bernhard Weiss (University of Cape Town), "Molecularity in the Theory of Meaning and the Topic Neutrality of Logic"

11:45 to 12:45: Nils Kürbis, (Ruhr University Bochum), "Deductive Semantics" 

13:00 to 14:00: Lunch 

14:00 to 15:00: Grigory Olkhovikov (Ruhr University Bochum), "Conditionals over some constructive logics"

15:15 to 16:15: Roberto Giuntini (University of Cagliari, TU Munich), "Machine Learning meets Quantum Mechanics"

19:00 Workshop Dinner at Karawane, Große Beckstraße 27, 44787 Bochum.


Acknowledgment

The Logic Day in Bochum is supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, grant agreement ERC-2020-ADG, 101018280, ConLog.

Abstracts

Bernhard Weiss, "Molecularity in the Theory of Meaning and the Topic Neutrality of Logic"

Abstract: The aim here is to uncover requirements on a justification of logic. The paper begins by endorsing and explaining a view of molecularity in the theory of meaning, conceived in terms of the notion of conservative extension. It raises Brandom inspired concerns about Dummett’s implementation of the view as a global requirement of harmony; but also sees a tension between Brandom’s holistic inferential view of meaning and his presumption that newly introduced vocabulary can incorporate inferential proprieties which are not affected by the very meanings introduced. I find a path between Brandom and Dummett, by accepting the Dummettian constraint of global conservativeness; but move towards Brandom by arguing that this need only be a tacit presupposition of speakers, and need not be demonstrable. Using Brandom’s notion of an autonomous discursive practice, I explain a notion of topic neutrality, arguing that logical vocabulary is topic neutral in this sense. The last phase of the paper combines these two thoughts—about conservative extensions and topic neutrality—to argue that logical vocabulary needs to be conceived of as demonstrably conservative with respect to any autonomous base vocabulary, because only if this is so can it be known to be topic neutral. This, combined with the fact that an assertor commits herself to providing her grounds for assertion, delivers a conception of harmony as a general constraint on the acceptability of a putative piece of logical vocabulary.


Nils Kürbis, "Deductive Semantics" 

Abstract: According to a common view going back to Gentzen, the meanings of logical expressions can be defined by the rules of inference governing them. This often forms part of a verificationist theory of meaning, in which the meanings of sentences are determined by the grounds that justify their assertion. But it can equally form part of a pragmatist theory of meaning, where the meanings of sentences are determined by the consequences of their assertions. In fact, according to Dummett, it should not matter which theory we choose, as these two aspects of use should be in harmony. The grounds and consequences of assertions should stand in a perfect balance, and one aspect is determined by the other. Following Dummett and Prawitz there is some consensus of how to spell out harmony when it comes to the logical constants. In a system of natural deduction the introduction rules for a connective specify the canonical grounds for asserting a formula with the expression as main operator, and the elimination rules their canonical consequences. The elimination rules should not license the deduction of more consequences from a formula than are justified by the grounds for inferring it as specified by the introduction rules for its main operator; and moreover they should allow the inference of all justified consequences. There is some consensus of what this means, but it leaves much implicit. In this talk I’ll propose a list of necessary conditions that rules of inference should satisfy if they are to define the meanings of the connectives they govern completely. They are motivated in part by logical, in part by more general meaning-theoretical considerations.  



Grigory Olkhovikov , "Conditionals over some constructive logics"

Abstract: We consider the question of finding the correct basic logic of conditionals conservatively extending a given constructive propositional logic. We focus on two cases in which the extended logic is either the intuitionistic or the paraconsistent variant of Nelson's logic of strong negation (often referred to as N4 in literature), respectively. In vindicating our replies to the said question in these two cases, we rely on the set of adequacy criteria set forth by A. Simpson (in A. Simpson. The Proof Theory and Semantics of Intuitionistic modal Logic, PhD Thesis, University of Edinburgh (1994)) for the intuitionistic modal logic, adapting their formulation to the particularities of our problem.

When discussing a version of Simpson's requirements for constructive conditional logics, we place the main weight upon  the existence of an explanation of conditional semantics in terms of the first-order version of the underlying constructive logic. We interpret this requirement as demanding the faithfulness of the embedding given by the classical notion of standard translation of conditional formulas.



Roberto Giuntini, "Machine Learning meets Quantum Mechanics"

Abstract: Research in the broad area of pattern recognition, machine learning, and quantum computing has inspired new ideas about some important general problems that arise in several disciplines, including information theory (classical and quantum), logic, cognitive science and neuroscience, and philosophy.

One of the fundamental questions that these disciplines often face is the following: How are abstract concepts formed and recognized on the basis of previous (natural or artificial) experiences? This problem has been studied, with a variety of methods and tools, both in the context of human intelligence and artificial intelligence.  In this seminar, the problem will be addressed within the framework of machine learning and quantum computing

Machine learning can be defined as the art and science of making computers learn from data how to solve problems (or recognize and classify new objects) without being explicitly programmed. Quantum computing describes the processing of information usiong tools based on the laws of quantum theory. Today, we are witnessing a dramatic explosion of data, and the problem of extracting and recognizing only “useful information’’ from these data is crucial but extremely resource consuming. On the other hand, quantum computing has shown that there exist quantum algorithms that allow a formidable acceleration in solving problems that, in their current state, would require exponential times. The realization of the so-called noisy intermediate-scale quantum (NISQ) computers is now a reality. Therefore, the combination of machine learning and   quantum computing appears inevitable. This "marriage" is favored by the fact that one of the fundamental features of quantum theory is that it can deal with incomplete information in a particularly natural and efficient way, a feature that is of primary importance in machine learning.  The approach that I will present in this seminar (called Quantum-Inspired Machine Learning) consists of formally translating the process of (supervised) classification of (classical) machine learning by using the formalism  of quantum theory in such a way that the resulting classification algorithms can be implemented on non-necessarily quantum computers. In particular, I will address the problem of binary classification of classical datasets, presenting a classifier (called the Helstrom Quantum Classifier (HQC), based on the Helstrom protocol, which is used to distinguish between two quantum states (mathematically represented by density matrices). HQC acts on density matrices, which, in our model, encode the patterns of a classical dataset. Experimental benchmark results show that, in many cases, the accuracy of HQC is superior to that of many classical classifiers. Finally, we will show how the improvement in HQC performance is positively correlated with the increase in the number of "quantum copies" of each (encoded) classical pattern.

1st Workshop on Contradictory Logics 

December 6–8, 2023

Ruhr University Bochum, Germany

https://sites.google.com/view/1stworkshoponcontradictorylogi/home


Acknowledgment

The 1st Workshop on Contradictory Logics is supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, grant agreement ERC-2020-ADG, 101018280, ConLog.


Second Bochum-Łodz Workshop on Logic 

Date & Venue


The second Bochum-Łodz Logic Workshop will be held in person in Bochum and online on the 17th and 18th of November. This time, the two ERC Advanced Grants held at the departments are the focus. The event provides an opportunity for the PIs of the grants and their collaborators and PhD students to present their work. Heinrich Wansing’s project “Contradictory Logics: ConLog: A Radical Challenge to Logical Orthodoxy” is held at the Department of Philosophy I of Ruhr Universität Bochum. Andrzej Indrzejczak’s project “ExtenDD: Coming to Terms: Proof Theory Extended to Definite Descriptions and other Terms” is held at the Department of Logic and Methodology of Science of the University of Lodz.


Program

Thursday, November 17.

14:00: Opening

14:15-14:45: Andrzej Indrzejczak "The coming to terms project: Extending proof theory by 𝜄"

14:45-15:15: Nils Kürbis "Definite descriptions via binary quantification"

15:30-16:00: Heinrich Wansing "The contradictory logics project"

16:00-16:30: Caitlin Canonica "Contradictions in the Wild; toward an experimental approach to contradictory logics"

Friday, November 18

10:00-11:00: Grigory Olkhovikov "On some first-order connexive logics"

11:15-12:15: Leonard Kupś "Methods of modelling linear time in hypersequent calculus"

12:15-12:45: Yaroslav Petrukhin "Cut-free sequent calculi for some three-valued logics obtained via correspondence analysis"

12:45-14:15: Lunch 

14:15-15:15: Satoru Niki "Provable contradictions and Kamide's negations"

15:30-16:00: Sara Ayhan "Two-sorted typed lambda-calculus for 2Int"

16:00-16:30: Michał Zawidzki "When iota meets lambda: The case of interpolation"

16:30-17:00: Przemysław Wałȩga "DatalogMTL: a logic for reasoning about temporal databases"


Acknowledgment

The second Bochum-Łodz Logic Workshop is supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, grant agreement ERC-2020-ADG, 101018280, ConLog.


Bochum Nonclassical Logic Workshop II

Aim

The aim of this workshop is to discuss and exchange new ideas and recent developments related to nonclassical logics, with an emphasis on constructive logics, relevant logics and conditional logics.

Date & Venue

Speakers


Program

10:15-11:15 Heinrich Wansing "Some remarks on conditional connexive logic"

11:15-11:30 Coffee

11:30-12:30 Hitoshi Omori "A note on Sasaki's conditional in view of Garson's question"

12:30-14:00 Lunch

14:00-15:00 Satoru Niki "Provable contradictions in constructive logics"

15:00-15:15 Coffee

15:15-16:15 Nicholas Ferenz "Some Results, Thoughts, and Historical Notes on Quantified (Modal) Relevant Logics"

16:15-16:30 Coffee

16:30-17:30 Andrew Tedder "The Algebraic Structure of Mares-Goldblatt Models"


Acknowledgment

The Bochum Nonclassical Logic Workshop II is supported by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, grant agreement ERC-2020-ADG, 101018280, ConLog, as well as by a Sofja Kovalevskaja Award of the Alexander von Humboldt-Foundation, funded by the German Ministry for Education and Research.