7 Directed Graphs, Finite State Machines 　 7.1 INTRODUCTION 7.2 DIRECTED GRAPHS 7.3 BASIC DEFINITIONS 7.4 DIGRAPHS, RELATIONS, NONNEGATIVE INTEGER SQUARE MATRICES 7.5 PRUNING ALGORITHM FOR MINIMAL PATH 7.6 FINAITE STATE MASHINES 7.7 STRINGE. INPUT AND OUTPUT TAPES 7.8 FINATE AUTOMATA