1971/02/01 by Amir Pnueli, A. Lempel, Shimon Even · 8 citations
Computer Science · Engineering · Mathematics · #Graph Labeling and Dimension Problems #graph theory and CDMA systems #Advanced Graph Theory Research #Combinatorics #Mathematics #Vertex (graph theory) #Permutation graph #Trapezoid graph #Orientation (vector space) #Transitive relation #Discrete mathematics #Graph #Chordal graph #1-planar graph #Geometry
paper · pdf · doi:10.4153/cjm-1971-016-5
openalex publication_date 1971/02/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
The graphs considered in this paper are assumed to be finite, with no edge joining a vertex to itself and with no two distinct edges joining the same pair of vertices. An undirected graph will be denoted by G or ( V, E ), where V is the set of vertices and E is the set of edges. An edge joining the vertices i,j ∊ V will be denoted by the unordered pair ( i,j ). An orientation of G = ( V, E ) is an assignment of a unique direction i → j or j → i to every edge ( i,j ) ∊ E . The resulting directed image of G will be denoted by G → or ( V , E→ ), where E→ is now a set of ordered pairs E→ = [ i,j ]| ( i,j ) ∊ E and i → j . Notice the difference in notation (brackets versus parentheses) for ordered and unordered pairs.