scholarly journals Maximal compatible extensions of partial orders

2006 ◽  
Vol 81 (2) ◽  
pp. 245-252 ◽  
Author(s):  
Stephan Foldes ◽  
Jenő Szigeti

AbstractWe give a complete description of maximal compatible partial orders on the mono-unary algebra (A, f), where f: A → A is an arbitrary unary operation.

2014 ◽  
Vol 91 (1) ◽  
pp. 104-115 ◽  
Author(s):  
SUREEPORN CHAOPRAKNOI ◽  
TEERAPHONG PHONGPATTANACHAROEN ◽  
PONGSAN PRAKITSRI

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.


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

2013 ◽  
Vol 846-847 ◽  
pp. 1304-1307
Author(s):  
Ye Wang ◽  
Yan Jia ◽  
Lu Min Zhang

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.


2000 ◽  
Vol 80 (2) ◽  
pp. 415-450 ◽  
Author(s):  
Bela Bollobas ◽  
Graham R. Brightwel
Keyword(s):  

2009 ◽  
Vol 02 (02) ◽  
pp. 201-212
Author(s):  
K. Denecke ◽  
Ch. Ratanaprasert

Iterating a unary operation f defined on the finite set A with |A| = k one obtains the descending chain [Formula: see text] The least integer λ(f) with Imfλ(f) = Imfλ(f)+1 is called the pre-period of f. The pre-period of f is an integer between 0 and k - 1. If λ(f) = k - 1 and k ≥ 1, then f is called a long-tailed (LT)-operation and if λ(f) = k - 2 for k ≥ 2, f is said to be an (LT1)-operation. Unary (LT)- and (LT1)-operations and their invariant equivalence relations are characterized in [5]. In [6] these results are extended to partial operations. In this paper we consider the iteration of n-ary operations for n > 1, define and characterize (LT)- and (LT1)- operations and their invariant equivalence relations. The results can be applied in all fields where iteration and recursion plays a role.


Order ◽  
1991 ◽  
Vol 8 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Tze-Heng Ma ◽  
Jeremy P. Spinrad
Keyword(s):  

1986 ◽  
Vol 78 (2) ◽  
pp. 179-192 ◽  
Author(s):  
William H.E. Day ◽  
Daniel P. Faith
Keyword(s):  

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