Pilling, D. L. Commutative regular equations and Parikh’s theorem. (English) Zbl 0277.68045 J. Lond. Math. Soc., II. Ser. 6, 663-666 (1973). Page: Show Scanned Page Cited in 6 Documents MSC: 68Q45 Formal languages and automata PDF BibTeX XML Cite \textit{D. L. Pilling}, J. Lond. Math. Soc., II. Ser. 6, 663--666 (1973; Zbl 0277.68045) Full Text: DOI OpenURL