http://hdl.handle.net/11089/42920 Mon, 06 Apr 2026 17:31:48 GMT 2026-04-06T17:31:48Z http://hdl.handle.net/11089/42929 Tableaux for some deontic logics with the explicit permission operator Glavaničová, Daniela; Jarmużek, Tomasz; Klonowski, Mateusz; Kulicki, Piotr In this paper we present a tableau system for deontic logics with the operator of explicit permission. By means of this system the decidability of the considered logics can be proved. We will sketch how these logics are semantically defined by means of relating semantics and how they provide a simple solution to the free choice permission problem. In short, these logics employ relating implication and a certain propositional constant. These two are in turn used to define deontic operators similarly as in Andersonian-Kangerian reduction, which uses different intensional implications and constants. Thu, 23 Jun 2022 00:00:00 GMT http://hdl.handle.net/11089/42929 2022-06-23T00:00:00Z http://hdl.handle.net/11089/42928 A Paradox for the Existence Predicate Meixner, Uwe In this paper, a paradox is shown to arise in the context of classical logic from prima facie highly plausible assumptions for the existence predicate as applied to definite descriptions. There are several possibilities to evade the paradox; all involve modifications in the principles of first-order logic with identity, existence, and definite descriptions; some stay within classical logic, others leave it. The merits of the various "ways out" are compared. The most attractive "way out," it is argued, stays within classical logic, except for the fact that it involves a new logical truth: "There is at least one non-existent object." But this "exit" will certainly not be to everyone's taste and liking. Thus, the paradox defies complete resolution (as every good paradox should). Fri, 10 Jun 2022 00:00:00 GMT http://hdl.handle.net/11089/42928 2022-06-10T00:00:00Z http://hdl.handle.net/11089/42927 A Classification of Improper Inference Rules Sasaki, Katsumi In the natural deduction system for classical propositional logic given by G. Gentzen, there are some inference rules with assumptions discharged by the rule. D. Prawitz calls such inference rules improper as opposed to proper ones. Improper inference rules are more complicated than proper ones and more difficult to understand. In 2022, we provided a sequent system based solely on the application of proper rules. In the present paper, on the basis of our system from 2022, we classify improper inference rules. Thu, 23 Jun 2022 00:00:00 GMT http://hdl.handle.net/11089/42927 2022-06-23T00:00:00Z http://hdl.handle.net/11089/42925 A Benchmark Similarity Measures for Fermatean Fuzzy Sets Khan, Faiz Muhammad; Khan, Imran; Ahmad, Waqas In this paper, we utilized triangular conorms (S-norm). The essence of using S-norm is that the similarity order does not change using different norms. In fact, we are investigating for a new conception for calculating the similarity of two Fermatean fuzzy sets. For this purpose, utilizing an S-norm, we first present a formula for calculating the similarity of two Fermatean fuzzy values, so that they are truthful in similarity properties. Following that, we generalize a formula for calculating the similarity of the two Fermatean fuzzy sets which prove truthful in similarity conditions. Finally, various numerical examples have been presented to elaborate this method. Wed, 08 Jun 2022 00:00:00 GMT http://hdl.handle.net/11089/42925 2022-06-08T00:00:00Z