A sharpening of the Parikh mapping
Faculty of Mathematics, University of Bucharest,
Academiei 14, Bucharest, Romania; (email@example.com)
2 Turku Centre for Computer Science, Lemminkäisenkatu 14, 20520 Turku, Finland; (firstname.lastname@example.org)
3 Department of Computing and Information Science, Queen's University, Kingston, Ontario K7L 3N6, Canada; (email@example.com)
4 Department of Computer Science, University of Western Ontario, London, Ontario N6A 5B7, Canada; (firstname.lastname@example.org)
Revised: 20 December 2001
In this paper we introduce a sharpening of the Parikh mapping and investigate its basic properties. The new mapping is based on square matrices of a certain form. The classical Parikh vector appears in such a matrix as the second diagonal. However, the matrix product gives more information about a word than the Parikh vector. We characterize the matrix products and establish also an interesting interconnection between mirror images of words and inverses of .
Mathematics Subject Classification: 68Q45 / 68Q70
Key words: Formal languages / Parikh mapping / scattered subwords.
© EDP Sciences, 2001