Title :
Ambiguity in Graphs and Expressions
Author :
Book, Ronald ; Even, Shimon ; Greibach, Sheila ; Ott, Gene
Author_Institution :
IEEE
Abstract :
A regular expression is called unambiguous if every tape in the event can be generated from the expression in one way only. The flow-graph technique for constructing an expression is shown to preserve ambiguities of the graph, and thus, if the graph is that of a deterministic automaton, the expression is unambiguous. A procedure for generating a nondeterministic automaton which preserves the ambiguities of the given regular expression is described. Finally, a procedure for testing whether a given expression is ambiguous is given.
Keywords :
Ambiguity of regular expressions, decidability of ambiguity, flow-graph algorithm, preservation of ambiguity of graphs, preservation of ambiguity of regular expressions.; Automata; Automatic testing; Books; Information science; Laboratories; Mathematics; Physics; Ambiguity of regular expressions, decidability of ambiguity, flow-graph algorithm, preservation of ambiguity of graphs, preservation of ambiguity of regular expressions.;
Journal_Title :
Computers, IEEE Transactions on
DOI :
10.1109/T-C.1971.223204
