# Word problems requiring exponential time(Preliminary Report)

@article{Stockmeyer1973WordPR, title={Word problems requiring exponential time(Preliminary Report)}, author={L. Stockmeyer and A. Meyer}, journal={Proceedings of the fifth annual ACM symposium on Theory of computing}, year={1973} }

The equivalence problem for Kleene's regular expressions has several effective solutions, all of which are computationally inefficient. In [1], we showed that this inefficiency is an inherent property of the problem by showing that the problem of membership in any arbitrary context-sensitive language was easily reducible to the equivalence problem for regular expressions. We also showed that with a squaring abbreviation ( writing (E)2 for E×E) the equivalence problem for expressions required… Expand

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