In memory of the distinguished logician, philosopher and political activist V.A. Yankov (1935 - 2024)

This session consists of four short presentations: **A brief overview of the biography of V.A. Yankov** (Kirill Yankov) **Yankov’s contributions to propositional logic** (Alex Citkin) The talk I will present two most significant contributions by V.A. Yankov: the Yankov Logic and Yankov characteristic formulas. **V.A. Yankov’s Contribution to the History and Philosophy of Mathematics** (Ioannis Vandoulakis) The talk will present three significant contributions of V.A. Yankov to the History and Philosophy of Mathematics: 1) By inviting A.A. Markov, the founder of the Russian school of constructivism and his teacher, to respond to Heyting’s fictional persons “Class,” “Form,” “Int,” “Pragm,” and “Sign,” which represent classical mathematics, formalism, intuitionism, pragmatism and significism, respectively, when he edited the Russian translation of Heyting’s Intuitionism. This response is the only historical record of Markov’s views on Brouwer’s intuitionistic mathematics and logic. 2) His appraisal of A.S. Esenin-Vol’pin’s program of ultra-intuitionistic foundations of mathematics stated in his commentary published in a volume dedicated to Esenin-Vol’pin by Finn and Daniel’ in 1999, in which he also included three less known and hardly accessible works of Esenin-Vol’pin [1967, 1971, 1999] devoted to the theory of modalities, deontic logic, the theory of disputes and the logic of trust. 3) His novel interpretation of the rise of mathematics and mathematical proof in ancient Greece. It is formulated by considering the development of the early Greek philosophers’ ontological conceptions. **V.A. Yankov’s existential research program** (Tatiana Denisova) In this talk, I will discuss the least known and, at the same time, the most controversial research program proposed by V.A. Yankov, namely his philosophical conception of the existential history of human thought, which is based on the idea of reconsidering the WHOLE history of human thought from an existential perspective. That means that the whole history of philosophy, regardless of the immediate subject of philosophers’ reasoning, is required to be reinterpreted as a history of “existential types”, i.e., as a history of the changes in the human’s self-understanding and the correlated changes in human’s understanding of the general picture of the world.