单调概念格性质研究

概念格是知识表示和数据分析的重要工具,单调概念格是概念格的推广。本文就Deogun等提出的单调概念格进行了两方面的研究:一,指出Deogun等提出的单调概念格性质的错误并加以修正;二,证明单调概念格就是闭格,从而找到用拓扑闭包算子和拓扑交结构来表示单调概念格的两种格表示方法,并建立起单调概念格与有上界的拓扑交结构的范畴等价。本文所建立的单调概念格的拓扑表示方法将方便我们进一步研究单调概念格的构造算法、约简算法和实际应用,具有理论和实际的双重意义。     

直觉模糊有限自动机的乘积

给出了直觉模糊有限自动机的广义直积、级联积和圈积及覆盖的定义,讨论了直觉模糊有限自动机在同构意义下级联积和圈积满足结合性以及各种乘积之间的覆盖关系。     

The isomorphism classes of the generalized Petersen graphs

In earlier work involving cycles in Generalized Petersen Graphs, we noticed some unexpected instances of P(m,k)≅P(m,l). In this article, all such instances are characterized. A formula is presented for the number of isomorphism classes of P(m,k).     

L-fuzzy商群的L-fuzzy同构定理

给出了L-fuzzy群的L-fuzzy同态基本定理。同时建立了L-fuzzy商群的L-fuzzy同态和L-fuzzy同构定理。     

Complement and Isomorphism on Bipolar Fuzzy Graphs

In this paper, we discuss some properties of the self complement and self weak complement bipolar fuzzy graphs, and get a sufficient condition for a bipolar fuzzy graph to be the self weak complement bipolar fuzzy graph. Also we investigate relations between operations union, join, and complement on bipolar fuzzy graphs.     

Isomorphism of bis(diethyldithiocarbamato)zinc(II) adduct with pyridine, [Zn(Py)(EDtc)2]: hysteresis in the reaction of the adduct formation

The structure of the polycrystalline adduct bis(diethyldithiocarbamato)-pyridine zinc(II) depends on the pathway of physico-chemical conditions during the preparation procedure, as was revealed by solid state ¹⁵N CP/MAS spectroscopy in good correlation with known single crystal X-ray diffraction structures of this adduct. Two isomorphs of the adduct, namely α-[Zn(Py)(S₂CNEt₂)₂] and β-[Zn(Py)(S₂CNEt₂)₂], are the two molecules in the asymmetric unit of a single crystal (or polycrystalline) sample that can be obtained by recrystallization from toluene of the equimolar solution of the initial diethyldithiocarbamate zinc(II) complex and pyridine. The third isomorph, γ-[Zn(Py)(S₂CNEt₂)₂], can be obtained by recrystallization from pure pyridine of the diethyldithiocarbamate zinc(II) complex, or by its equimolar absorption of pyridine, or by desorption of pyridine from the clathrated adduct, [Zn(Py)(S₂CNEt₂)₂]·Py. Finally, the γ-[Zn(Py)(S₂CNEt₂)₂] isomorph recrystallizes from the melt into α/β-isomorphs of the adduct.     

The isotone mappings on Ockham algebras

In this paper we shall describe some algebraic concepts of Ockham algebras. We show that, ifL, M K _1,1 thenH(S(L),S(M)) S(H(L,M)).     

Maximum agreement and compatible supertrees

Given a set of leaf-labelled trees with identical leaf sets, the MAST problem, respectively MCT problem, consists of finding a largest subset of leaves such that all input trees restricted to these leaves are isomorphic, respectively compatible. In this paper, we propose extensions of these problems to the context of supertree inference, where input trees have non-identical leaf sets. This situation is of particular interest in phylogenetics. The resulting problems are called SMAST and SMCT.A sufficient condition is given that identifies cases where these problems can be solved by resorting to MAST and MCT as subproblems. This condition is met, for instance, when only two input trees are considered. Then we give algorithms for SMAST and SMCT that benefit from the link with the subtree problems. These algorithms run in time linear to the time needed to solve MAST, respectively MCT, on an instance of the same or smaller size.It is shown that arbitrary instances of SMAST and SMCT can be turned in polynomial time into instances composed of trees with a bounded number of leaves.SMAST is shown to be W[2]-hard when the considered parameter is the number of input leaves that have to be removed to obtain the agreement of the input trees. A similar result holds for SMCT. Moreover, the corresponding optimization problems, that is the complements of SMAST and SMCT, cannot be approximated in polynomial time within any constant factor, unless P=NP. These results also hold when the input trees have a bounded number of leaves.The presented results apply to both collections of rooted and unrooted trees.     

Sur la détermination d'une relation binaire à partir d'informations locales

This paper deals with the problematic aspect of the reconstruction of binary relations: it includes all the questions raising the possibility or impossibility to determine a structure by gathering given substructures. It is the continuation of three studies: the first made by G. Lopez [9] in 1972 about the determination of a binary relation through the types of isomorphism of its restrictions, the second made by K. B. Reid and C. Thomassen [15] in 1976 about the strongly self-complementary tournaments (every subtournament is self-complementary), the third made by C. Thomassen [16] in 1989 about the cycle space of a tournament. In the second section, we use the notion of class of difference (which was introduced in [9]) to extend a study made in [16] to binary relations. Then, in the third section, we improve the result of this last study in the case of the tournaments. After noticing that the result of [15] inferred itself naturally from the approach developed in [9], we extend, in the fourth section, the study made in [15] to binary relations.     

On the Isomorphism Conjecture in algebraic K-theory

The Isomorphism Conjecture is a conceptional approach towards a calculation of the algebraic K-theory of a group ring RΓ, where Γ is an infinite group. In this paper we prove the conjecture in dimensions n<2 for fundamental groups of closed Riemannian manifolds with strictly negative sectional curvature and arbitrary coefficient rings R. If R is regular this leads to a concrete calculation of low dimensional K-theory groups of RΓ in terms of the K-theory of R and the homology of the group.