The class of commutative dually residuated lattice ordered monoids ($DR\ell $-monoids) contains among others Abelian lattice ordered groups, algebras of Hájek’s Basic fuzzy logic and Brouwerian algebras. In the paper, a unary operation of negation in bounded $DR\ell $-monoids is introduced, its properties are studied and the sets of regular and dense elements of $DR\ell $-monoids are described.
Systems of axioms for elementary logic we can find in textbooks are usually not very transparent; and the reader might well wonder how did precisely such a set of axioms come into being. In this paper we present a way of constituting one such non-transparent set of axioms, namely the one presented by E. Mendelson in his Introduction to Mathematical Logic, in a transparent way, with the aim of helping the reader to get an insight into the workings of the axioms., Systémy axiomů pro elementární logiku, které můžeme najít v učebnicích, nejsou obvykle příliš transparentní; a čtenář by se mohl divit, jak přesně vznikl takový soubor axiomů. V tomto příspěvku představujeme způsob, jak vytvořit jednu takovou netransparentní sadu axiomů, a to transparentní způsob, který předložil E. Mendelson ve svém Úvodu do matematické logiky , s cílem pomoci čtenáři nahlédnout do fungování axiomů., and Jaroslav Peregrin
Uninorms, as binary operations on the unit interval, have been widely applied in information aggregation. The class of almost equitable uninorms appears when the contradictory information is aggregated. It is proved that among various uninorms of which either underlying t-norm or t-conorm is continuous, only the representable uninorms belong to the class of almost equitable uninorms. As a byproduct, a characterization for the class of representable uninorms is obtained.