ContributionsTree-visibility orders

We introduce a new class of partially ordered sets, called tree-visibility orders, containing interval orders, duals of generalized interval orders and height one orders. We give a characterization of tree-visibility orders by an infinite family of minimal forbidden suborders. Furthermore, we present an efficient recognition algorithm for tree-visibility orders.     

Inductive Characterizations of Finite Interval Orders and Semiorders

We introduce an inductive definition for two classes of orders. By simple proofs, we show that one corresponds to the interval orders class and that the other is exactly the semiorders class.     

New matrix partial order based on spectrally orthogonal matrix decomposition

We investigate partial orders on the set of complex square matrices and introduce a new order relation based on spectrally orthogonal matrix decompositions. We also establish the relation of this concept with the known orders.     

GENERALIZED BRAUER ALGEBRAS

ABSTRACT

Using some ideas of Brauer, we introduce what we call generalized Brauer algebras and, as a special case, Brauer orders. We show that many well-known classes of so-called crossed product algebras, and in particular, the well-known crossed product orders, can be obtained as special instances of our construction. We prove several results showing when Brauer orders are Azumaya, maximal, hereditary or Gorenstein.     

Shuffle-compatible total orders

Sunto We introduce the concept of shuffle- and union-compatibility of total orders on words over a finite alphabet. This works only in a graded manner respecting the length of words. We classify all such orders by even exhibiting a normal form. For union-compatibility we draw on experience gained in a generalisation of Kruskal's packing theorem, as well as in working with rigidified surjections, for shuffle compatibility we also draw on Saizeva-Trevisan's characterisation of compatible total orders on finitely generated free commutative groups.     

Transitive Oriented 3 Hypergraphs of Cyclic Orders

In this paper we introduce the definition of transitivity for oriented 3-hypergraphs in order to study partial and complete cyclic orders. This definition allows us to give sufficient conditions on a partial cyclic order to be totally extendable. Furthermore, we introduce the 3-hypergraph associated to a cyclic permutation and characterize it in terms of cyclic comparability 3-hypergraphs.     

Numerical Representation of Semiorders

We introduce a codomain to represent semiorders, total preorders and interval orders by means of a single map. We characterize the semiorders that are representable in the extended real line.     

Maximal Condorcet Domains

A Condorcet domain is a subset of the set of linear orders on a finite set of candidates (alternatives to vote), such that if voters preferences are linear orders belonging to this subset, then the simple majority rule does not yield cycles. It is well-known that the set of linear orders is the Bruhat lattice. We prove that a maximal Condorcet domain is a distributive sublattice in the Bruhat lattice. An explicit lattice formula for the simple majority rule is given. We introduce the notion of a symmetric Condorcet domain and characterize symmetric Condorcet domains of maximal size.     

Auslander–Reiten quiver and representation theories related to KLR-type Schur–Weyl duality

Mathematische Zeitschrift - We introduce new partial orders on the sequence positive roots and study the statistics of the poset by using Auslander–Reiten quivers for finite type ADE. Then we...     

Fountain-Gould Left Orders for Associative Pairs

In this paper, we introduce a notion of weak Fountain-Gould left order for associative pairs and give a Goldie-like theory of associative pairs which are weak Fountain Gould left orders in semiprime pairs coinciding with their socles.     

The vertex isoperimetric problem for the powers of the diamond graph

We introduce a new graph for all whose cartesian powers the vertex isoperimetric problem has nested solutions. This is the fourth kind of graphs with this property besides the well-studied graphs like hypercubes, grids, and tori. In contrast to the mentioned graphs, our graph is not bipartite. We present an exact solution to the vertex isoperimetric problem on our graph by introducing a new class of orders that unifies all known isoperimetric orders defined on the cartesian powers of graphs.     

Two Order Invariants Related to the Fixed Point Property

We introduce two numerical invariants of orders that measure how close a poset is to having the fixed point property. We give general properties of those invariants and link them to known results on the fixed point property.     

Economic lot-sizing games

In this paper we introduce a new class of OR games: economic lot-sizing (ELS) games. There are a number of retailers that have a known demand for a fixed number of periods. To satisfy demand the retailers order products at the same manufacturer. By placing joint orders instead of individual orders, costs can be reduced and a cooperative game arises. In this paper we show that ELS games are balanced. Furthermore, we show that two special classes of ELS games are concave.     

Some Truncated Distributions

Long-tailed distributions arise in many areas of the sciences. These distributions, however, suffer from the weakness of not having finite moments of all orders and this weakness has restricted their use. In this note, we introduce truncated versions of five of the most commonly known long-tailed distributions—which possess finite moments of all orders and could therefore be better models. Explicit expressions for the moments are derived for each of the truncated distributions. Several applications are illustrated using real data.     

Optimal scheduling on parallel machines for a new order class

This paper addresses the problem of scheduling n unit length tasks on m identical machines under certain precedence constraints. The aim is to compute minimal length nonpreemptive schedules. We introduce a new order class which contains properly two rich families of precedence graphs: interval orders and a subclass of the class of series parallel orders. We present a linear time algorithm to find an optimal schedule for this new order class on any number of machines.     

Tilting bundles on orders on ℙd

We introduce a class of orders on ?^d called Geigle-Lenzing orders and show that they have tilting bundles. Moreover we show that their module categories are equivalent to the categories of coherent sheaves on Geigle- Lenzing projective spaces introduced in [HIMO].     

Generalized Growth Orders for Polymonogenic Functions and Related Inequalities

In this paper we introduce generalized growth orders and growth types in the sense of Shah and Seremeta in the context of polymonogenic functions. They provide a refinement of previously introduced growth orders in the study of the asymptotic growth behavior of functions satisfying higher dimensional Cauchy–Riemann type equations. We prove a number of insight giving inequalities and manage to extend some basic results that were recently proved for the context of the usual first order Cauchy–Riemann system in Clifford analysis.     

Topogenous and Nearness Structures on Categories

We introduce topogenous orders on a general category and demonstrate that they are equivalent to neighbourhood operators and subsume both closure and interior operators. By looking at the basic properties of so-called strict morphisms relative to a topogenous order the ease of working with their axioms and the concurrent generalisation of both interior and closure is evident. In closing we consider Herrlich’s concept of nearness in a category and how it interacts with topogenous orders and syntopogenous structures.     

Partial symmetry, reflection monoids and Coxeter groups

This is the first of a series of papers in which we initiate and develop the theory of reflection monoids, motivated by the theory of reflection groups. The main results identify a number of important inverse semigroups as reflection monoids, introduce new examples, and determine their orders.     

The L* Partial Order on the Set of Group Matrices

In this paper,we use the L(o)wner partial order and the star partial order to introduce a new partial order (denoted by "L*") on the set of group matrices,and get some characteristics and properties of the new partial order.In particular,we prove that the L* partial order is a special kind of the core par-tial order and it is equivalent to the star partial order under some conditions.We also illustrate its difference from other partial orders with examples and find out under what conditions it is equivalent to other partial orders.