scholarly journals Maximal elements under the three partial orders

1992 ◽  
Vol 175 ◽  
pp. 39-61 ◽  
Author(s):  
Robert E. Hartwig ◽  
Raphael Loewy
Keyword(s):  
Partial Orders ◽  
Maximal Elements

scholarly journals Undominated Groves Mechanisms

2013 ◽  
Vol 46 ◽  
pp. 129-163 ◽  
Author(s):  
M. Guo ◽  
E. Markakis ◽  
K. R. Apt ◽  
V. Conitzer
Keyword(s):  
Partial Orders ◽  
Strict Inequality ◽  
Maximal Elements ◽  
Total Utility ◽  
Vcg Mechanism ◽  
The Family ◽  
Groves Mechanisms ◽  
Groves Mechanism ◽  
Strategy Proof

The family of Groves mechanisms, which includes the well-known VCG mechanism (also known as the Clarke mechanism), is a family of efficient and strategy-proof mechanisms. Unfortunately, the Groves mechanisms are generally not budget balanced. That is, under such mechanisms, payments may flow into or out of the system of the agents, resulting in deficits or reduced utilities for the agents. We consider the following problem: within the family of Groves mechanisms, we want to identify mechanisms that give the agents the highest utilities, under the constraint that these mechanisms must never incur deficits. We adopt a prior-free approach. We introduce two general measures for comparing mechanisms in prior-free settings. We say that a non-deficit Groves mechanism M individually dominates another non-deficit Groves mechanism M' if for every type profile, every agent's utility under M is no less than that under M', and this holds with strict inequality for at least one type profile and one agent. We say that a non-deficit Groves mechanism M collectively dominates another non-deficit Groves mechanism M' if for every type profile, the agents' total utility under M is no less than that under M', and this holds with strict inequality for at least one type profile. The above definitions induce two partial orders on non-deficit Groves mechanisms. We study the maximal elements corresponding to these two partial orders, which we call the individually undominated mechanisms and the collectively undominated mechanisms, respectively.

scholarly journals Natural Partial Orders on Transformation Semigroups with Fixed Sets

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yanisa Chaiya ◽  
Preeyanuch Honyam ◽  
Jintana Sanwong
Keyword(s):  
Partial Order ◽  
Partial Orders ◽  
Natural Partial Order ◽  
Transformation Semigroups ◽  
Maximal Elements ◽  
Fixed Subset ◽  
Regular Monoid

LetXbe a nonempty set. For a fixed subsetYofX, letFixX,Ybe the set of all self-maps onXwhich fix all elements inY. ThenFixX,Yis a regular monoid under the composition of maps. In this paper, we characterize the natural partial order onFix(X,Y)and this result extends the result due to Kowol and Mitsch. Further, we find elements which are compatible and describe minimal and maximal elements.

scholarly journals PARTIAL ORDERS ON SEMIGROUPS OF PARTIAL TRANSFORMATIONS WITH RESTRICTED RANGE

2012 ◽  
Vol 86 (1) ◽  
pp. 100-118 ◽  
Author(s):  
KRITSADA SANGKHANAN ◽  
JINTANA SANWONG
Keyword(s):  
Partial Order ◽  
Partial Orders ◽  
Natural Partial Order ◽  
Restricted Range ◽  
Maximal Elements

AbstractLet X be any set and P(X) the set of all partial transformations defined on X, that is, all functions α:A→B where A,B are subsets of X. Then P(X) is a semigroup under composition. Let Y be a subset of X. Recently, Fernandes and Sanwong defined PT(X,Y )={α∈P(X):Xα⊆Y } and defined I(X,Y ) to be the set of all injective transformations in PT(X,Y ) . Hence PT(X,Y ) and I(X,Y ) are subsemigroups of P(X) . In this paper, we study properties of the so-called natural partial order ≤ on PT(X,Y ) and I(X,Y ) in terms of domains, images and kernels, compare ≤ with the subset order, characterise the meet and join of these two orders, then find elements of PT(X,Y ) and I(X,Y ) which are compatible. Also, the minimal and maximal elements are described.

THE NATURAL PARTIAL ORDER ON LINEAR SEMIGROUPS WITH NULLITY AND CO-RANK BOUNDED BELOW

2014 ◽  
Vol 91 (1) ◽  
pp. 104-115 ◽  
Author(s):  
SUREEPORN CHAOPRAKNOI ◽  
TEERAPHONG PHONGPATTANACHAROEN ◽  
PONGSAN PRAKITSRI
Keyword(s):  
Semigroup Forum ◽  
Partial Order ◽  
Lower Bounds ◽  
Partial Orders ◽  
Natural Partial Order ◽  
Linear Transformations ◽  
Bounded Below

AbstractHiggins [‘The Mitsch order on a semigroup’, Semigroup Forum 49 (1994), 261–266] showed that the natural partial orders on a semigroup and its regular subsemigroups coincide. This is why we are interested in the study of the natural partial order on nonregular semigroups. Of particular interest are the nonregular semigroups of linear transformations with lower bounds on the nullity or the co-rank. In this paper, we determine when they exist, characterise the natural partial order on these nonregular semigroups and consider questions of compatibility, minimality and maximality. In addition, we provide many examples associated with our results.

Modeling country risk ratings using partial orders

2006 ◽  
Vol 175 (2) ◽  
pp. 836-859 ◽  
Author(s):  
P.L. Hammer ◽  
A. Kogan ◽  
M.A. Lejeune
Keyword(s):  
Country Risk ◽  
Partial Orders

Frequent Closed Partial Orders Mining in Sequences

2013 ◽  
Vol 846-847 ◽  
pp. 1304-1307
Author(s):  
Ye Wang ◽  
Yan Jia ◽  
Lu Min Zhang
Keyword(s):  
Sequence Data ◽  
Real Data ◽  
Partial Orders ◽  
Hard Problem ◽  
Important Data ◽  
Data Set ◽  
Pruning Algorithm ◽  
Equal Chance ◽  
Np Hard Problem ◽  
General Sequences

Mining partial orders from sequence data is an important data mining task with broad applications. As partial orders mining is a NP-hard problem, many efficient pruning algorithm have been proposed. In this paper, we improve a classical algorithm of discovering frequent closed partial orders from string. For general sequences, we consider items appearing together having equal chance to calculate the detecting matrix used for pruning. Experimental evaluations from a real data set show that our algorithm can effectively mine FCPO from sequences.

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