By H. B. Hunt, J. D. Ullman, T. G. Szymanski
Communications of the ACM,
March 1977,
Vol. 20 No. 3, Pages 171-176
10.1145/359436.359446
Comments
Various computations on relations, Boolean matrices, or directed graphs, such as the computation of precedence relations for a context-free grammar, can be done by a practical algorithm that is asymptotically faster than those in common use. For example, how to compute operator precedence or Wirth-Weber precedence relations in O(n2) steps is shown, as well as how to compute linear precedence functions in O(n) steps, where n is the size of a grammar. The heart of the algorithms is a general theorem giving sufficient conditions under which an expression whose operands are sparse relations and whose operators are composition, transitive closure, union, and inverse, can be computed efficiently.
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