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91.
Radomír Halaš 《Studia Logica》2008,89(1):19-35
It has been recently shown [4] that the lattice effect algebras can be treated as a subvariety of the variety of so-called
basic algebras. The open problem whether all subdirectly irreducible distributive lattice effect algebras are just subdirectly
irreducible MV-chains and the horizontal sum of two 3-element chains is in the paper transferred into a more tractable one. We prove that modulo distributive lattice
effect algebras, the variety generated by MV-algebras and is definable by three simple identities and the problem now is to check if these identities are satisfied by all distributive
lattice effect algebras or not.
Presented by Daniele Mundici 相似文献
92.
A continuous stochastic logic with a μ-operator μCSL is defined, and an interpretation through stochastic relations is proposed. We investigate morphisms for models of μCSL, showing that the associated congruences can be used for an investigation of bisimilarity. The Hennessy–Milner equivalence for μCSL is discussed, and it is shown that models are equivalent iff they are bisimilar, using a general criterion for bisimilarity from the theory of stochastic relations. 相似文献
93.
94.
The logic RM and its basic fragments (always with implication) are considered here as entire consequence relations, rather than as sets of theorems. A new observation made here is that the disjunction of RM is definable in terms of its other positive propositional connectives, unlike that of R. The basic fragments of RM therefore fall naturally into two classes, according to whether disjunction is or is not definable. In the equivalent quasivariety semantics of these fragments, which consist of subreducts of Sugihara algebras, this corresponds to a distinction between strong and weak congruence properties. The distinction is explored here. A result of Avron is used to provide a local deduction-detachment theorem for the fragments without disjunction. Together with results of Sobociski, Parks and Meyer (which concern theorems only), this leads to axiomatizations of these entire fragments — not merely their theorems. These axiomatizations then form the basis of a proof that all of the basic fragments of RM with implication are finitely axiomatized consequence relations.Special issue of Studia Logica: Algebraic Theory of Quasivarieties Presented by
M. E. Adams, K. V. Adaricheva, W. Dziobiak, and A. V. Kravchenko 相似文献
95.
Alexander Budkin 《Studia Logica》2004,78(1-2):107-127
The dominion of a subalgebra H in an universal algebra A (in a class
) is the set of all elements
such that for all homomorphisms
if f, g coincide on H, then af = ag. We investigate the connection between dominions and quasivarieties. We show that if a class
is closed under ultraproducts, then the dominion in
is equal to the dominion in a quasivariety generated by
. Also we find conditions when dominions in a universal algebra form a lattice and study this lattice.Special issue of Studia Logica: Algebraic Theory of Quasivarieties Presented by
M. E. Adams, K. V. Adaricheva, W. Dziobiak, and A. V. Kravchenko 相似文献
96.
97.
In this paper, we further investigate the consistency problem for the qualitative temporal calculus introduced by Pujari et al. [A.K. Pujari, G.V. Kumari, A. Sattar, INDU: An interval and duration network, in: Australian Joint Conference on Artificial Intelligence, 1999, pp. 291–303]. We prove the intractability of the consistency problem for the subset of pre-convex relations, and the tractability of strongly pre-convex relations. Furthermore, we also define another interesting set of relations for which the consistency problem can be decided by the -closure method, a method similar to the usual path-consistency method. Finally, we prove that the -closure method is also complete for the set of atomic relations of implying that the intervals have the same duration. 相似文献
98.
99.
100.
We introduce Łukasiewicz-Moisil relation algebras, obtained by considering a relational dimension over Łukasiewicz-Moisil
algebras. We prove some arithmetical properties, provide a characterization in terms of complex algebras, study the connection
with relational Post algebras and characterize the simple structures and the matrix relation algebras. 相似文献