EJC
2006
14 years 28 days ago
2006
: Two transformations are constructed that map the permutation group onto a well-defined subset of a partially commutative monoid generated by the so-called oiseaux. Those transfor...
EJC
2006
14 years 28 days ago
2006
We introduce a large self-dual class of simplicial complexes for which we show that each member complex is contractible or homotopy equivalent to a sphere. Examples of complexes i...
EJC
2006
14 years 28 days ago
2006
The problem of counting plane trees with n edges and an even or an odd number of leaves has been recently studied by Eu, Liu and Yeh, in connection with an identity on coloring ne...
34
Voted
EJC
2006
14 years 28 days ago
2006
Abstract. We start with a bijective proof of Schur's theorem due to Alladi and Gordon and describe how a particular iteration of it leads to some very general theorems on colo...
EJC
2006
14 years 28 days ago
2006
Abstract. A leaf of a plane tree is called an old leaf if it is the leftmost child of its parent, and it is called a young leaf otherwise. In this paper we enumerate plane trees wi...
EJC
2006
14 years 28 days ago
2006
A tube (resp. an oval tube) in PG(3, q) is a pair T = {L, L}, where {L} L is a collection of mutually disjoint lines of PG(3, q) such that for each plane of PG(3, q) containing L...
EJC
2006
14 years 28 days ago
2006
EJC
2006
14 years 28 days ago
2006
We study the positive Bergman complex B+ (M) of an oriented matroid M, which is a certain subcomplex of the Bergman complex B(M) of the underlying unoriented matroid M. The positiv...
EJC
2006
14 years 28 days ago
2006
In this paper we study the sequence (ci)0id for a distance-regular graph. In particular we show that if d 2j and cj = c > 1 then c2j > c holds. Using this we give improveme...
EJC
2006
14 years 2 months ago
2006
: In this paper we describe a solution for the semi-automatic ontology based text annotation (OnTeA) tool. The tool analyzes a document or text using regular expression patterns an...