edited by Do Long Van (Institute of Mathematics, Vietnam) & M Ito (Kyoto Sangyo University, Japan)

This volume presents research results ranging from those in pure mathematical theory (semigroup theory, graph theory, etc.) to those in theoretical and applied computer science, e.g. formal languages, automata, codes, parallel and distributed computing, formal systems, knowledge systems and database theory.

• On an Infinite Hierarchy of Petri Net Languages (P T An & P V Thao)
• Algorithms to Test Rational ω-Codes (X Augros & I Litovsky)
• Longest Cycles and Restgraph in Maximal Non-Hamiltonian Graphs (V D Hoa)
• Deterministic and Nondeterministic Directable Automata (M Ito)
• Worst-Case Redundancy of Solid Codes (H Jürgensen & S Konstantinidis)
• Maximal Independent Sets in Certain Subword Orders (N H Lam)
• Strong Recognition of Rational ω-Languages (B L Saëc et al.)
• Some Results Concerning Covers in the Class of Multivalued Positive Boolean Dependencies (L D Minh et al.)
• The Complexity of Problems Defined by Boolean Circuits (S Reith & K W Wagner)
• The Rational Skimming Theorem (J Sakarovitch)
• A New Classification of Finite Simple Groups (W Shi & S Lipschutz)
• Connectedness of Tetravalent Metacirculant Graphs with Non-Empty First Symbol (N D Tan & T M Tuoc)
• and other papers