Human beings are called logical animals because they are endowed with the ability to reason. Logic is a science that deals with the rules and processes used in reasoning and as such plays a fundamental and foundational role throughout science. As part of the World Logic Day 2026 logicians across the globe are invited to join in a virtual event on 14 January 2026 to celebrate the World Logic Day in Nigeria. 

This year we will focus on Logic and its application (including but not limited to AI).

The zoom meeting will be featuring talks around the role and applications of logic (classical and non-classical) in different areas of research, and it is open to anyone interested in logic in the fields of Mathematics, Philosophy, Computer Science and other related areas.

The registered participants can be found here.

INTUITIONISTIC FUZZY TENDENCY COEFFICIENT-BASED WEIGHTED DISTANCE MEASURE WITH APPLICATIONS

Paul Augustine Ejegwa (Joseph Sarwuan Tarka University)

Abstract: Decision-making (DM), a fundamental aspect of human endeavor, is often hindered by uncertainty and imprecision. Intuitionistic fuzzy sets (IFSs) have proven effective in addressing these challenges, particularly through the use of distance measures. Although numerous distance-measuring approaches under IFSs have been proposed in the literature, existing methods largely overlook both the tendency coefficients of intuitionistic fuzzy parameters and the weights of the underlying elements. To bridge this gap, this paper introduces a novel distance measure for IFSs based on weighted tendency coefficients, offering enhanced flexibility and discriminatory power compared to existing techniques. The effectiveness and applicability of the proposed distance measure are demonstrated through its use in pattern recognition and disease diagnosis problems.

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FRAMES FOR MATHEMATICAL TEXTS

Deniz Sarikaya (Universität zu Lübeck)

Abstract: We discuss the concept of frames with respect to mathematical texts. The concept of frames has been developed in the context of Artificial Intelligence since the 1970s, but recently also in linguistics and philosophy. We defend the following theses:

1. Frames can be used to model both (textual) structural properties of proofs and ontological aspects of mathematical knowledge, and to relate both aspects of proof understanding.

2. Specifically, using frames it is possible to model how mathematicians understand proofs texts where patterns have not been executed in a fully explicit way.

3. The inheritance hierarchy of frames allows, among others, to represent generalization and creative application of proof methods.

4. They have some intersting philosophical consequences esp. in the areas of "understanding" and "innovation".

This is joint work with Bernhard Fisseni and Bernhard Schröder.

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WHAT IS EQUALITY?

Thorsten Altenkirch (University of Nottingham) 

Abstract:  Equality is one of the most fundamental notions in mathematics and logic, yet also one of the most subtle. In this talk, we examine different notions of equality arising in type theory: definitional equality, propositional

equality, and observational equality.

We discuss why equality cannot simply be identified with syntactic identity, how computation and proof interact, and how higher-dimensional notions of equality naturally emerge. The talk culminates in an overview of Higher Observational Type Theory, where equality is treated as structured data rather than a mere proposition.

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CAN LOGIC BE POSSIBLY USEFUL IN SCIENCE? 

Andrei Rodin (Smolny Beyond Borders)  

Abstract: In my talk I'll overview some past and some recent attempts to apply logical methods in science, and try to outline some directions for future research. More specifically I’ll focus on the Justification Logic and akin logical approaches based on Type theory,  and show their relevance in prospective Knowledge Representation  techniques.