Search results for "Isomorphism"

Surfaces of minimal degree of tame representation type and mutations of Cohen–Macaulay modules

2017

We provide two examples of smooth projective surfaces of tame CM type, by showing that any parameter space of isomorphism classes of indecomposable ACM bundles with fixed rank and determinant on a rational quartic scroll in projective 5-space is either a single point or a projective line. For surfaces of minimal degree and wild CM type, we classify rigid Ulrich bundles as Fibonacci extensions. For the rational normal scrolls S(2,3) and S(3,3), a complete classification of rigid ACM bundles is given in terms of the action of the braid group in three strands.

Artin groups of spherical type up to isomorphism

2003

AbstractWe prove that two Artin groups of spherical type are isomorphic if and only if their defining Coxeter graphs are the same.

Unit Operations in Approximation Spaces

2010

Unit operations are some special functions on sets. The concept of the unit operation originates from researches of U. Wybraniec-Skardowska. The paper is concerned with the general properties of such functions. The isomorphism between binary relations and unit operations is proved. Algebraic structures of families of unit operations corresponding to certain classes of binary relations are considered. Unit operations are useful in Pawlak's Rough Set Theory. It is shown that unit operations are upper approximations in approximation space. We prove, that in the approximation space (U, R) generated by a reflexive relation R the corresponding unit operation is the least definable approximation i…

Social Entrepreneurship as a Form of Institutional Entrepreneurship

2021

Bureaucracy as a form of structuring and working of current organizations may be seen as the result of a set of circumstances. For Weberians, bureaucracy is the consequence of the principles of protestant values applied to the market. For institutionalists, bureaucracy is the outcome of the replication of practices in organizations, that is, bureaucracy is due to isomorphism among organizations. Following the institutional approach, organizations act by imitation. This imitation provides a certain way to compete and work necessary to survival, meaning that this imitation gives stability and equilibrium to the context in which organizations operate. Nevertheless, this equilibrium may not be …

Two groups with isomorphic group algebras

1990

Models and Phenomena: Bas van Fraassen’s Empiricist Structuralism

2013

Bas van Fraassen’s recent endorsement of empiricist structuralism is based on a particular approach to representation. He sharply distinguishes between what makes a scientific model M a successful representation of its target T from what makes M a representation of T and not of some other different target T’. van Fraassen maintains that embedment (i.e.: a particular sort of isomorphism which relates structures) gives the answer to the first question while the user’s decision to employ model M to represent T accounts for the representational link. After discussing the rationale for this approach, I defend that indexical constraints like those favoured by van Fraassen cannot be the last word …

AUDIENCE SUPPORT DECISIONS IN IN THE AFTERMATH OF A SOCIAL SCANDAL: THE ROLES OF LEGITIMACY AND REPUTATION

2014

Constituent audience evaluations and decisions regarding whether to continue to support a corporation after it has been perceived as culpable for socially irresponsible behaviour following corporate social irresponsibility (CSI) scandals are coin of the realm in selecting which firms (or which parts of a firm) will be able to survive a CSI-scandal. Research has largely taken for granted that CSI leads to the loss of corporate legitimacy and, consequently, of constituent audience support. Though legitimacy may be reconstructed, empirics suggest this is a necessary but insufficient condition for the maintenance of audience support. Adopting the evaluators’ perspective, this study focuses on t…

An Algebraic Approach to Knowledge Representation

1999

This paper is an attempt to apply domain-theoretic ideas to a new area, viz. knowledge representation. We present an algebraic model of a belief system. The model consists of an information domain of special kind (belief algebra) and a binary relation on it (entailment). It is shown by examples that several natural belief algebras are, essentially, algebras of flat records. With an eye on this, we characterise those domains and belief algebras that are isomorphic to domains or algebras of records. For illustration, we suggest a system of axioms for revision in such a model and describe an explicit construction of what could be called a maxichoise revision.

Pattern Matching and Pattern Discovery Algorithms for Protein Topologies

2001

We describe algorithms for pattern-matching and pattern-learning in TOPS diagrams (formal descriptions of protein topologies). These problems can be reduced to checking for subgraph isomorphism and finding maximal common subgraphs in a restricted class of ordered graphs. We have developed a subgraph isomorphism algorithm for ordered graphs, which performs well on the given set of data. The maximal common subgraph problem then is solved by repeated subgraph extension and checking for isomorphisms. Despite its apparent inefficiency, this approach yields an algorithm with time complexity proportional to the number of graphs in the input set and is still practical on the given set of data. As a…

Specht property for some varieties of Jordan algebras of almost polynomial growth

2019

Abstract Let F be a field of characteristic zero. In [25] it was proved that U J 2 , the Jordan algebra of 2 × 2 upper triangular matrices, can be endowed up to isomorphism with either the trivial grading or three distinct non-trivial Z 2 -gradings or by a Z 2 × Z 2 -grading. In this paper we prove that the variety of Jordan algebras generated by U J 2 endowed with any G-grading has the Specht property, i.e., every T G -ideal containing the graded identities of U J 2 is finitely based. Moreover, we prove an analogue result about the ordinary identities of A 1 , a suitable infinitely generated metabelian Jordan algebra defined in [27] .