The protagonist of Thomas Mann’s short story "The Clown" cannot became an artist because he hasn’t got enough talent. He is also unable to live among people as an ordinary citizen because his social competencies haven’t been completely developed. That is why he can be regarded as a literary figure who tries to leave the real world and to penetrate the literary world. The devil who appears in Charles Gounod’s opera "Faust" based on Johann Wolfgang Goethe’s drama "Faust" and who (...) is watching the protagonist from the stage during the opera performance seems to be the only person who can help him to find his existential space. (shrink)

In the paper, pre-Hilbert algebras are defined as a generalization of Hilbert algebras (namely, a Hilbert algebra is just a pre-Hilbert algebra satisfying the property of antisymmetry). Pre-Hilbert algebras have been inspired by Henkin's Positive Implicative Logic. Their properties and characterizations are investigated. Some important results and examples are given. Moreover, positive implicative pre-Hilbert algebras are introduced and studied, their connections with some algebras of logic are presented. The hierarchies existing between the classes of algebras considered here are shown.

The article is devoted to present Polish research on the literary work and philosophical thought of Hryhorii Skovoroda. The scientific reflection on Skovoroda’s legacy was initially carried out on the historical and literary level. It was initiated by Adam Honory Kirkor in 1874. In the context of the history of Ukrainian literature, Józef Tretiak, Ivan Franko and Bohdan Lepkyi presented the general characteristics of Skovoroda’s work, seeing in it only the original style and compilation character of thoughts. Ivan Mirtchuk started (...) his research on Skovoroda’s thoughts from the history of national philosophy, seeing in Skovoroda’s philosophy the features charac- teristic of Ukrainian philosophy, differing it fundamentally from Russian philosophy. As part of the research, it was possible to find an extensive article by Jarosław Ulwański, Philosophy of G.S. Skovoroda, published in 1930, in which the author presented arguments for a pantheistic interpretation of the Ukrainian philosopher’s thoughts. A breakthrough event was the publication of a monograph by Dmytro Tschižewskij, who formulated a view on the mystical philosophy of Skovoroda similar to the Western European mysticism of the 17th and 18th centuries. The interwar period ends with the work of Czesław Jastrzębiec-Kozłowski, in which the work of Skovoroda was analyzed against the background of Józef Hoene-Wronski’s messianic philosophy. After World War II and the 1990s, research on Skovoroda’s legacy was conducted primarily by philologists. Ryszard Łużny and Włodzimierz Mokry treated Skovoroda’s work as a Christian philosopher. In the 21st century, Polish research increasingly refers to philosophical interpretation. Denys Pilipowicz researched the ancient and patristic sources of Skovoroda’s mystical thought and compared it with the teachings of Paisij Velyczkovskyi. Iryna Betko analyzed his poetry from the perspective of Jung’s theory of archetypes. Michał Handzel conducted an in-depth historical and philosophical analysis of Skovoroda’s philosophy, seeing Skovoroda as a representative of the panentheistic trend, and Pavlo Snopkov examined the concept of Skovoroda’s self-knowledge from the perspective of Jung’s and Maslow’s psychological theories. (shrink)

The paper consists of two parts, outlined in the title.I. In the historical science time appears as an element of the historian’s workshop. The historian collects source information, evaluates them and assigns respective dates. Only on the ground of thus “processed” sources may he reproduce the past: events and longer development processes, setting them in time. This dated time is understood colloquially as something objective, which runs one way and may be measured.II. A historian who studies the past reality depends (...) on the extent to which those sources are preserved. As a result of their interpretation, with the use of increasingly excellent research methods, he reproduces that reality. He must carry out an ongoing selection of historical facts found. This exposes him to temptations of such selection of those facts so as to adjust the historical knowledge to serve well the national interests, his own political opinions, etc. In this way the historian exerts influence on social awareness, which may consists of various myths and stereotypes, which sometimes lead to negative social behaviors: aggression, chauvinism, etc. Therefore, for researcher honesty’s sake and in the sense of moral responsibility, he must be careful to be as impartial as possible in his work. (shrink)

The main aim of the present paper is to explain a nature of relationships exist between Nelson and Heyting algebras. In the realization, a topological duality theory of Heyting and Nelson algebras based on the topological duality theory of Priestley for bounded distributive lattices are applied. The general method of construction of spaces dual to Nelson algebras from a given dual space to Heyting algebra is described. The algebraic counterpart of this construction being a generalization of the Fidel-Vakarelov construction is (...) also given. These results are applied to compare the equational category N of Nelson algebras and some its subcategories with the equational category H of Heyting algebras. It is proved that the category N is topological over the category H. (shrink)

This article focuses on the trajectory of life of the three generations of the Jankowski family in Siberia, Primorski Krai and Korea in the years 1863– 1945 in terms of their economic, cultural and scientific achievements. The founder of the Far Eastern branch of the family was Michał Jankowski. Exiled to Siberia for participation in the January Uprising of 1863, as a man of indefatigable energy and collaborator of Benedykt Dybowski, he undertook many initiatives, including hunting, wild ginseng collecting and (...) a gold mining administration. In 1880 he settled on the Sidiemi Peninsula near Vladivostok, where he established a farm specializing in horse breeding and ginseng gardening. In addition to farming, he conducted natural history and archaeological research and sent the acquired specimens and artifacts to Russian and European museums. The tradition of his father was continued in the second generation by Jerzy Mikhailovich Jankowski. Endowed with similar character and talent, he studied agriculture and husbandry in Texas and at the agricultural faculty of St. Louis University in Missouri. He expanded the farm to include commercial fishing and rice cultivation. The occupation of the Far East by the Red Army in 1922 forced the family to emigrate to Korea and Manchuria. The new family seat called Novina was built on the Ompo River near the town of Ch’ŏngjin, about 200 kilometers south along the Korean coastline from the mouth of the Tuman River. It was not only a modern farm with specialized animal husbandry and fruit farming, but was also a recreational, cultural, and spiritual enclave, with a school for children, a summer theater, an Orthodox church, and a resort for holidaymakers. The third and the most famous representative of the family was Walery Jurewicz Jankowski. In 1945, he joined the Soviet Army, where, due to his knowledge of Korean and Japanese, he served as an interpreter for the military intelligence at the headquarters of the 25th Army in P’yŏngyang. At the beginning of 1946, both Walery and his fathers were arrested and sent to the labor camps. The family was scattered around the world, from Australia to the North and Latin Americas and the farm was nationalized. The Jankowsky family achieved spectacular success in the Russian Far East and in Korea because they were able to apply the traditional Polish gentry ethos based on the extended structure of family and servants, which they were able to combine with a chivalrous fortitude and openness to hard life in the frontiers populated by various ethnic groups. (shrink)

This book provides a detailed exposition of one of the most practical and popular methods of proving theorems in logic, called Natural Deduction. It is presented both historically and systematically. Also some combinations with other known proof methods are explored. The initial part of the book deals with Classical Logic, whereas the rest is concerned with systems for several forms of Modal Logics, one of the most important branches of modern logic, which has wide applicability.

Natural Deduction Natural Deduction is a common name for the class of proof systems composed of simple and self-evident inference rules based upon methods of proof and traditional ways of reasoning that have been applied since antiquity in deductive practice. The first formal ND systems were independently constructed in the 1930s by G. Gentzen and S. Jaśkowski and … Continue reading Natural Deduction →.

During the global financial crisis of 2007–2009 and the currentCovid-19 debacle, central banks acted quickly, boldly, and effectively. The paper argues that they did so thanks to the lessons learned from the past financial crises, which provided them with opportunities to reconsider their previous beliefs. A case in point is the banking crisis in the United States during the Great Depression of the 1930s that taught central banks to act rapidly and decisively in order to prevent an initial liquidity crisis (...) from escalating into a solvency crisis leading to bankruptcies of banks with potentially disastrous consequences for the entire economy. The paper revisits the consequences of the currency crises of the 1990s, which transformed exchange rate regimes across the world: the EMS one of 1992–1993 that accelerated the launch of the euro, and the Asian one of 1997–1998 resulted in the proliferation of floating exchange rates in emerging economies. (shrink)

A new type of formalization of classical first-order logic with equality is introduced on the basis of the sequent calculus. It serves to justify the claim that equality is a logical constant characterised by well-behaved rules satisfying properties usually regarded as essential. The main feature of this approach is the application of sequents built not only from formulae but also from terms. Two variants of sequent calculus are examined, a structural and a logical one. The former is defined in accordance (...) with Dos̆en’s criteria for logical constants. The latter is a standard Gentzen’s sequent calculus and satisfies Hacking’s criteria for logicality, including cut elimination. It is also shown that provided rules are harmonious in the sense advocated by Gratzl and Orlandelli. (shrink)

The paper presents a uniform proof-theoretic treatment of several kinds of free logic, including the logics of existence and definedness applied in constructive mathematics and computer science, and called here quasi-free logics. All free and quasi-free logics considered are formalised in the framework of sequent calculus, the latter for the first time. It is shown that in all cases remarkable simplifications of the starting systems are possible due to the special rule dealing with identity and existence predicate. Cut elimination is (...) proved in a constructive way for sequent calculi adequate for all logics under consideration. (shrink)

We examine some extensions of the constructive propositional logic with strong negation in the setting of varieties of $\mathcal{N}$ -lattices. The main aim of the paper is to give a description of all pretabular, primitive and preprimitive varieties of $\mathcal{N}$ -lattices.

Nicolae Iorga jest postacią o dużym znaczeniu w historii i kulturze Rumunii. Bardzo często wypowiadał się o sprawach polskich w szerokim tego słowa znaczeniu, zarówno w kwestiach akademickich, jak i politycznych. Zaangażowanie Iorgi w Polskę jest widoczne niemal nieprzerwanie w trakcie jego kariery naukowej i politycznej. Od czasów szkolnych po jego tragiczną śmierć Polska i jej sprawy były obecne w jego działalności także za sprawą jego nauczycieli, profesorów czy późniejszych partnerów politycznych. Dzięki wykształceniu historycznemu Iorga postrzegał Polskę jako ważnego partnera (...) Rumunii na arenie międzynarodowej, jako gwarancję bezpieczeństwa politycznego, ale także ważnego partnera w kontekście rozwoju kulturalnego. Jako inicjator kursów języka i kultury rumuńskiej na Uniwersytecie Jagiellońskim, Nicolae Iorga otrzymał tytuł doktora honoris causa Uniwersytetu Wileńskiego w 1931 r. za ważną rolę w umacnianiu stosunków między Polską a Rumunią. (shrink)

In several applications of sequent calculi going beyond pure logic, an introduction of suitably defined rules seems to be more profitable than addition of extra axiomatic sequents. A program of formalization of mathematical theories via rules of special sort was developed successfully by Negri and von Plato. In this paper a general theorem on possible ways of transforming axiomatic sequents into rules in sequent calculi is proved. We discuss its possible applications and provide some case studies for illustration.

This paper is concerned with n-localization property introduced by Newelski and Rosłanowski in [10] and getting it for CS iterations of forcing notions.

Hypersequent calculus, developed by A. Avron, is one of the most interesting proof systems suitable for nonclassical logics. Although HC has rather simple form, it increases significantly the expressive power of standard sequent calculi. In particular, HC proved to be very useful in the field of proof theory of various nonclassical logics. It may seem surprising that it was not applied to temporal logics so far. In what follows, we discuss different approaches to formalization of logics of linear frames and (...) provide a cut-free HC formalization ofKt4.3, the minimal temporal logic of linear frames, and some of its extensions. The novelty of our approach is that hypersequents are defined not as finite sets but as finite lists of ordinary sequents. Such a solution allows both linearity of time flow, and symmetry of past and future, to be incorporated by means of six temporal rules. Extensions of the basic calculus with simple structural rules cover logics of serial and dense frames. Completeness is proved by Schütte/Hintikka-style argument using models built from saturated hypersequents. (shrink)

The paper contains an exposition of some non standard approach to gentzenization of modal logics. The first section is devoted to short discussion of desirable properties of Gentzen systems and the short review of various sequential systems for modal logics. Two non standard, cut-free sequent systems are then presented, both based on the idea of using special modal sequents, in addition to usual ones. First of them, GSC I is well suited for nonsymmetric modal logics The second one, GSC II (...) is devised specially for symmetric, i.e. Blogics. GSC I and GSC II are not different formalizations, from the theoretical point of view GSC I may be seen as a simplification of the more general approach present in GSC II. They are considered separately, mainly because Blogics demand different, and more complicated, strategy in completeness proof, whereas non symmetric logics are easily and uniformly characterised by means of Fitting's Consistency Properties. The weakest modal logic captured by this formalization is minimal regular logic C, but many stronger logics are obtainable by addition of suitable structural rules, which conforms to Do en's methodology. Both variants of GSC satisfy also other, besides cut-freedom, desirable properties. (shrink)

We provide an application of a sequent calculus framework to the formalization of definite descriptions. It is a continuation of research undertaken in [20, 22]. In the present paper a so-called free description theory is examined in the context of different kinds of free logic, including systems applied in computer science and constructive mathematics for dealing with partial functions. It is shown that the same theory in different logics may be formalised by means of different rules and gives results of (...) varying strength. For all presented calculi a constructive cut elimination is provided. (shrink)

We study axiomatic extensions of the propositional constructive logic with strong negation having the disjunction property in terms of corresponding to them varieties of Nelson algebras. Any such varietyV is characterized by the property: (PQWC) ifA,B V, thenA×B is a homomorphic image of some well-connected algebra ofV.We prove:• each varietyV of Nelson algebras with PQWC lies in the fibre –1(W) for some varietyW of Heyting algebras having PQWC, • for any varietyW of Heyting algebras with PQWC the least and the (...) greatest varieties in –1(W) have PQWC, • there exist varietiesW of Heyting algebras having PQWC such that –1(W) contains infinitely many varieties (of Nelson algebras) with PQWC. (shrink)