An improved algorithm for transitive closure on acyclic digraphs

Let D be a digraph, V ( D ) and A ( D ) will denote the sets of vertices and arcs of D , respectively. A subset N of V ( D ) is k -independent if for every pair of vertices u , v N , we have d ( u , v ) , d ( v , u ) k ; it is l -absorbent if for every ...

Chordal graphs are important in the structural and algorithmic graph theory. A digraph analogue of chordal graphs was introduced by Haskin and Rose in 1973 but has not been the subject of active studies until recently when a ...

Reid [Every vertex a king, Discrete Math. 38 (1982) 93-98] showed that a non-trivial tournament H is contained in a tournament whose 2-kings are exactly the vertices of H if and only if H contains no transmitter. Let T be a semicomplete multipartite ...