Title
The Number of Unlabeled Orders on Fourteen Elements
Abstract
Abstract Lacking an explicit formula for the numbers T0(n) of all order relations (equivalently: T0 topologies) on n elements, those numbers have been explored only up to n = 13 (unlabeled posets) and n = 15 (labeled posets), respectively In a new approach, we used an orderly algorithm to (i) generate each unlabeled poset on up to 14 elements and (ii) collect enough information about the posets on 13 elements to be able to compute the number of labeled posets on 16 elements by means of a formula by Erne Unlike other methods, our algorithm avoids isomorphism tests and can therefore be parallelized quite easily The underlying principle of successively adding new elements to small objects is applicable to lattices and other kinds of order structures, too
Year
DOI
Venue
2000
10.1023/A:1006431609027
A Journal on The Theory of Ordered Sets and Its Applications
Keywords
Field
DocType
enumeration,finite poset,orderly algorithm,parallelization,topology
Discrete mathematics,Combinatorics,Enumeration,Star product,Mathematics
Journal
Volume
Issue
ISSN
17
4
1572-9273
Citations 
PageRank 
References 
10
2.49
3
Authors
2
Name
Order
Citations
PageRank
Jobst Heitzig1458.07
Jürgen Reinhold2315.89