共查询到20条相似文献,搜索用时 31 毫秒
1.
Ivor Grattan-Guinness 《Theology & Science》2013,11(1):137-147
An important feature of mathematics, both pure and applied, during the nineteenth century was the widening from its common form to a proliferation, where the “objects” studied were not numbers or geometrical magnitudes but operations such as functions and differentiation and integration, abstract ones (as we now call them), linear algebras of vectors, matrices and determinants, and algebras in logic. In this article the author considers several of them, including the contributions of Hermann Grassmann and Benjamin Peirce. A notable feature of these developments was analogising from one algebra to another by adopting some of the same laws, such as associativity, commutativity and distributivity. In the final section we consider the normally secular character of these algebras. 相似文献
2.
Miklós Ferenczi 《Studia Logica》2007,87(1):1-11
It is known that every α-dimensional quasi polyadic equality algebra (QPEA
α
) can be considered as an α-dimensional cylindric algebra satisfying the merrygo- round properties . The converse of this proposition fails to be true. It is investigated in the paper how to get algebras in QPEA from algebras
in CA. Instead of QPEA the class of the finitary polyadic equality algebras (FPEA) is investigated, this class is definitionally
equivalent to QPEA. It is shown, among others, that from every algebra in a β-dimensional algebra can be obtained in QPEA
β
where , moreover the algebra obtained is representable in a sense.
Presented by Daniele Mundici
Supported by the OTKA grants T0351192, T43242. 相似文献
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We show that not all epimorphisms are surjective in certain classes of infinite dimensional cylindric algebras, Pinter's substitution
algebras and Halmos' quasipolyadic algebras with and without equality. It follows that these classes fail to have the strong
amalgamation property. This answers a question in [3] and a question of Pigozzi in his landmark paper on amalgamation [9].
The cylindric case was first proved by Judit Madarasz [7]. The proof presented herein is substantially different. By a result
of Németi, our result implies that the Beth-definability Theorem fails for certain expansions of first order logic 相似文献
6.
Marta A. Zander 《Studia Logica》2008,88(2):233-246
In this paper we prove that, for n > 1, the n-generated free algebra in any locally finite subvariety of HoRA can be written in a unique nontrivial way as Ł2 × A′, where A′ is a directly indecomposable algebra in . More precisely, we prove that the unique nontrivial pair of factor congruences of is given by the filters and , where the element is recursively defined from the term introduced by W. H. Cornish. As an additional result we obtain a characterization of minimal irreducible filters of in terms of its coatoms.
Presented by Daniele Mundici 相似文献
7.
8.
Diego Vaggione 《Studia Logica》1996,57(2-3):239-241
It is proved that the directly indecomposable algebras in a congruence modular equational class form a first-order class provided that fulfils some two natural assumptions.Research supported by CONICOR and SECYT (UNC).Presented by W. Dziobiak 相似文献
9.
SC
, CA
, QA
and QEA
stand for the classes of Pinter's substitution algebras, Tarski's cylindric algebras, Halmos' quasipolyadic algebras, and quasipolyadic equality algebras of dimension , respectively. Generalizing a result of Németi on cylindric algebras, we show that for K {SC, CA, QA, QEA} and ordinals < , the class Nr
K
of -dimensional neat reducts of -dimensional K algebras, though closed under taking homomorphic images and products, is not closed under forming subalgebras (i.e. is not a variety) if and only if > 1.From this it easily follows that for 1 < < , the operation of forming -neat reducts of algebras in K
does not commute with forming subalgebras, a notion to be made precise.We give a contrasting result concerning Halmos' polyadic algebras (with and without equality). For such algebras, we show that the class of infinite dimensional neat reducts forms a variety.We comment on the status of the property of neat reducts commuting with forming subalgebras for various reducts of polyadic algebras that are also expansions of cylindric-like algebras. We try to draw a borderline between reducts that have this property and reducts that do not.Following research initiated by Pigozzi, we also emphasize the strong tie that links the (apparently non-related) property of neat reducts commuting with forming subalgebras with proving amalgamation results in cylindric-like algebras of relations. We show that, like amalgamation, neat reducts commuting with forming subalgebras is another algebraic expression of definability and, accordingly, is also strongly related to the well-known metalogical properties of Craig, Beth and Robinson in the corresponding logics. 相似文献
10.
11.
We consider various classes of algebras obtained by expanding idempotent semirings with meet, residuals and Kleene-*. An investigation of congruence properties (e-permutability, e-regularity, congruence distributivity) is followed by a section on algebraic Gentzen systems for proving inequalities in idempotent semirings, in residuated lattices, and in (residuated) Kleene lattices (with cut). Finally we define (one-sorted) residuated Kleene lattices with tests to complement two-sorted Kleene algebras with tests. 相似文献
12.
Roberto Cignoli 《Studia Logica》1996,56(1-2):23-29
The dual spaces of the free distributive lattices with a quantifier are constructed, generalizing Halmos' construction of the dual spaces of free monadic Boolean algebras. 相似文献
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In [4], Caicedo and Cignoli study compatible functions on Heytingalgebras and the corresponding logical properties of connectivesdefined on intuitionistic propositional calculus. In this paperwe study some aspects of compatible functions on the algebrasassociated to positive propositional calculus and successiveextensions of it: intuitionistic calculus itself, the modalsymmetric propositional calculus of Moisil and n-valued ukasiewiczpropositional calculus. 相似文献
18.
Tarek Sayed Ahmed 《Studia Logica》2008,89(3):325-332
Following research initiated by Tarski, Craig and Németi, and futher pursued by Sain and others, we show that for certain
subsets G of
ω
ω, atomic countable G polyadic algebras are completely representable. G polyadic algebras are obtained by restricting the similarity type and axiomatization of ω-dimensional polyadic algebras to finite quantifiers and substitutions in G. This contrasts the cases of cylindric and relation algebras.
Presented by Robert Goldblatt 相似文献
19.
Part I of this paper is developed in the tradition of Stone-type dualities, where we present a new topological representation for general lattices (influenced by and abstracting over both Goldblatt's [17] and Urquhart's [46]), identifying them as the lattices of stable compact-opens of their dual Stone spaces (stability refering to a closure operator on subsets). The representation is functorial and is extended to a full duality.In part II, we consider lattice-ordered algebras (lattices with additional operators), extending the Jónsson and Tarski representation results [30] for Boolean algebras with Operators. Our work can be seen as developing, and indeed completing, Dunn's project of gaggle theory [13, 14]. We consider general lattices (rather than Boolean algebras), with a broad class of operators, which we dubb normal, and which includes the Jónsson-Tarski additive operators. Representation of l-algebras is extended to full duality.In part III we discuss applications in logic of the framework developed. Specifically, logics with restricted structural rules give rise to lattices with normal operators (in our sense), such as the Full Lambek algebras (F L-algebras) studied by Ono in [36]. Our Stone-type representation results can be then used to obtain canonical constructions of Kripke frames for such systems, and to prove a duality of algebraic and Kripke semantics for such logics. 相似文献
20.
In this paper we show that the subvarieties of BL, the variety of BL-algebras, generated by single BL-chains on [0, 1], determined by continous t-norms, are finitely axiomatizable. An algorithm to check the subsethood relation between these subvarieties is provided, as well as another procedure to effectively find the equations of each subvariety. From a logical point of view, the latter corresponds to find the axiomatization of every residuated many-valued calculus defined by a continuous t-norm and its residuum. Actually, the paper proves the results for a more general class than t-norm BL-chains, the so-called regular BL-chains. 相似文献