排序方式: 共有29条查询结果,搜索用时 31 毫秒
1.
Weakly associative lattice rings (wal-rings) are non-transitive generalizations of lattice ordered rings (l-rings). As is known, the class of l-rings which are subdirect products of linearly ordered rings (i.e. the class of f-rings) plays an important role in the theory of l-rings. In the paper, the classes of wal-rings representable as subdirect products of to-rings and ao-rings (both being non-transitive generalizations of the class of f-rings) are characterized and the class of wal-rings having lattice ordered positive cones is described. Moreover, lexicographic products of weakly associative lattice groups are also studied here. 相似文献
2.
Alain A. Lewis 《Mathematical Social Sciences》1985,10(1):43-80
Let X be a compact, convex subset of Rn, and let be a recursive space of alternatives, where R(X) is the image of X in a recursive metric space, and is the family of all recursive subsets of R(X). If is a non-trivial recursively representable choice function that is rational in the sense of Richter, we prove that C has no recursive realization within Church's Thesis. Our proof is not a diagonalization argument and uses no paradoxical statements from formal systems. Instead, the proof is a Kleene-Post reduction style argument and uses the Turing equivalence between mechanical devices of computation and the recursive functions of Gödel and Kleene. 相似文献
3.
李思泽 《南昌大学学报(理科版)》1989,13(2):1
V称是一个格序群(或1-群)簇,若V中元是1-群,且V关于1-子群闭、1-同态象闭、基数直积闭。本文讨论了弱阿贝尔1-群簇在可表1-群簇内的幂的若干性质,它们是T·Feil关于阿贝尔1-群簇的幂的定理和命题的推广,并且给出了弱何贝尔1-群簇的若干等价条件。 相似文献
4.
定义了向量筐函数的C-Stieltjes近似可表示算子,并研究了它的性质。另外,我们定义了向量值函数的近似C-Stieltjes积分,并证明了它的收敛定理。 相似文献
5.
Alain A. Lewis 《Mathematical Social Sciences》1985,10(2):179-188
We show that the minimum degree of Turing complexity of a recursively representable choice function is Õ″, the degree of a complete ∑2 set in the Kleene-Mostowski hierarchy. A consequence of this result is that the complexity of such choice functions in this sense is bounded strictly above the degrees of R.E. subsets on . 相似文献
6.
Alex M. McAllister 《Mathematical Logic Quarterly》2002,48(2):245-259
We examine the relationship between two different notions of a structure being Scott set saturated and identify sufficient conditions which guarantee that a structure is uniquely Scott set saturated. We also consider theories representing Scott sets; in particular, we identify a sufficient condition on a theory T so that for any given countable Scott set there exists a completion of T that is saturated with respect to the given Scott set. These results extend Scott's characterization of countable Scott sets via models and completions of Peano arithmetic. 相似文献
7.
A. Ya. Belov 《Siberian Advances in Mathematics》2007,17(4):227-267
The subject of this work is an extension of A. R. Kemer’s results to a rather broad class of rings close to associative rings, over a field of characteristic 0 (in particular, this class includes the varieties generated by finite-dimensional alternative and Jordan rings). We prove the finite-basedness of systems of identities (the Specht property), the representability of finitely-generated relatively free algebras, and the rationality of their Hilbert series. For this purpose, we extend the Razymslov-Zubrilin theory to Kemer polynomials. For a rather broad class of varieties, we prove Shirshov’s theorem on height. 相似文献
8.
Madjid Allili Tomasz Kaczynski 《Transactions of the American Mathematical Society》2000,352(5):2261-2281
This paper is devoted to giving the theoretical background for an algorithm for computing homomorphisms induced by maps in homology. The principal idea is to insert the graph of a given continuous map into a graph of a multi-valued representable map . The multi-valued representable maps have well developed continuity properties and admit a finite coding that permits treating them by combinatorial methods. We provide the construction of the homomorphism induced by such that . The presented construction does not require subsequent barycentric subdivisions and simplicial approximations of . The main motivation for this paper comes from the project of computing the Conley Index for discrete dynamical systems.
9.
Alfio Giarlotta 《Order》2004,21(1):29-41
A linear ordering is said to be representable if it can be order-embedded into the reals. Representable linear orderings have
been characterized as those which are separable in the order topology and have at most countably many jumps. We use this characterization
to study the representability of a lexicographic product of linear orderings. First we count the jumps in a lexicographic
product in terms of the number of jumps in its factors. Then we relate the separability of a lexicographic product to properties
of its factors, and derive a classification of representable lexicographic products.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
10.
Nick Bezhanishvili 《Algebra Universalis》2002,48(1):11-42
We investigate the lattice of all subvarieties of the variety Df
2 of two-dimensional diagonal-free cylindric algebras. We prove that a Df
2-algebra is finitely representable if it is finitely approximable, characterize finite projective Df
2-algebras, and show that there are no non-trivial injectives and absolute retracts in Df
2. We prove that every proper subvariety of Df
2 is locally finite, and hence Df
2 is hereditarily finitely approximable. We describe all six critical varieties in , which leads to a characterization of finitely generated subvarieties of Df
2. Finally, we describe all square representable and rectangularly representable subvarieties of Df
2.
Received May 25, 2000; accepted in final form November 2, 2001. 相似文献