The 7th annual (International) Krasnoyarsk Logical Workshop, dedicated to the World Logic Day, traditionally took place on January 14th.

What is special about January 14th?

• January 14 - New Year according to the Julian calendar;
• January 14, 1901 - the birthday of Alfred Tarski;
• January 14, 1978 - the day of the death of Kurt Gödel.

Like last years, now we again hold it in a mixed format.

• everyone could took part in full-time participation in the seminar without prior registration in room 34-17 of the Institute of Mathematics and Computer Science of the Siberian Federal University (Krasnoyarsk, Svobodny ave., 79).
• online participation is possible with pre-registration. The link to the event will be available only to registered participants.

Participation was available to everyone (including junior students).

Recall that the first workshop in support of Jean-Yves Béziau's initiative to recognize January 14 as World Logic Day took place in 2019. In 2020-22 it has been held as an official even of the World Logic Day project of UNESCO through CIPSH (Conseil International de Philosophie et des Sciences Humaines):
2nd Krasnoyarsk Logical Workshop
3rd Krasnoyarsk Logical Workshop
4th Krasnoyarsk Logical Workshop
5th Krasnoyarsk Logical Workshop became international.
6th and this 7th Krasnoyarsk Logical Workshops were retained this status.

The event was supported by Department of Algebra and Mathematical Logic and Krasnoyarsk Mathematical Center. Information and technical support for the event is traditionally provided by IM&CS Youth Center.

Applications for participation with a report was accepted until January 13, 18:00 local time (CET+6).

The 7th annual Krasnoyarsk Logical Workshop, dedicated to the World Logic Day, took place on January 14th between 16:00 and 21:00 local time (CET+6).

In 2020, already in the status of a UNESCO official date, we successfully organized the 2nd workshop (for more details, see here).

In 2021, amid the coronavirus pandemic, the Krasnoyarsk Logical Workshop was held online in the form of the Zoom conference as an official even of the World Logic Day project of UNESCO through CIPSH (Conseil International de Philosophie et des Sciences Humaines). The third KLW became the largest in terms of geography and the number of members: it included 16 participants, among them, 2 doctors and 7 candidates of sciences, 6 undergraduate and graduate students, and one post-graduate student.

In 2022, the workshop was held in a mixed format with covid-free restrictions for participants. In 2023 all of Russian seminars have lost the status of an official event, however, we have gained the international level of our workshop. In 2024 and 2025 we are again part of a large international project by Jean-Yves Béziau: 2024, 2025.

Organizing Committee:
Stepan I. Bashmakov (chairman), Kirill Smelykh and Elizaveta Brylyakova.

Within the framework of the workshop, there will be several reports — with a methodological and historical nature, and setting out new scientific results. The traditional coffee break, dedicated to the celebration of the traditional Russian holiday — Old New Year — will also take place.

We started the meeting at 16:00 local time (10:00 CET). The programm of the meeting is available here.

16:00 - the beginning of the meeting. Introductory speech by Stepan I. Bashmakov.

• 16:15 Andrey V. Kudinov (Steklov Mathematical Institute of RAS, Moscow) - "Finite model property of some pretransitive modal logics" (online);
• 17:05 Larisa L. Maksimova, Veta F. Yun (Institute of Mathematics of SB RAS, Novosibirsk) - "An example of logics with the interpolation property ~CIP, the sum of which does not have CIP" (online);
• 17:35 Nikolay V. Shilov (Innopolis University, Tatarstan) - "What is the formal semantics of programs?" (online);
• 18:15 Sergey I. Todikov (Saint Petersburg Electrotechnical University “LETI”, Saint Petersburg) - "Theory of Multi-operation: From Closed Sets to Artificial Intelligence" (online).

18:40 - virtual/real coffee break
18:55 - the second half of the meeting

• 18:55 Sergei P. Odintsov (Institute of Mathematics of SB RAS, Novosibirsk) - Weakly implicative logics: approaches to defining definitional equivalence and definability (online);
• 19:40 Elizaveta V. Brylyakova (SibFU, Krasnoyarsk) - "How to proof of the finite type of unification in pretabular superintuitionistic logics";
• 20:00 Tatyana Yu. Zvereva (SibFU, Krasnoyarsk) - "Linear step-like logic of knowledge LTK.sl and its knowledge-depleted version";
• 20:15 Aleksandr A. Polyakov (SibFU, Krasnoyarsk) - "Tuple semantics for temporal logics, including branching case";
• 20:30 Kirill A. Smelykh (SibFU, Krasnoyarsk) - "On decidability and model checking in the Logics of Computing Trees".

20:45 - the ending of the meeting.

The 7th workshop became the longest due to the number of reports, as well as their variety and volume.