منابع مشابه
A sharpening of the Parikh mapping
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...
متن کاملCodifiable Languages and the Parikh Matrix Mapping
We introduce a couple of families of codifiable languages and investigate properties of these families as well as interrelationships between different families. Also we develop an algorithm based on the Earley algorithm to compute the values of the inverse of the Parikh matrix mapping over a codifiable context-free language. Finally, an attributed grammar that computes the values of the Parikh ...
متن کاملA q-Matrix Encoding Extending the Parikh Matrix Mapping
We introduce a generalization of the Parikh mapping called the Parikh q-matrix encoding, which takes its values in matrices with polynomial entries. The encoding represents a word w over a k-letter alphabet as a (k + 1)-dimensional upper-triangular matrix with entries that are nonnegative integral polynomials in variable q. Putting q = 1, we obtain the morphism introduced by Mateescu, Salomaa, ...
متن کاملOn the Injectivity of the Parikh Matrix Mapping
In this paper we investigate the injectivity of the Parikh matrix mapping. This research is done mainly on the binary alphabet. We identify a family of binary words, refered to as “palindromicly amicable”, such that two such words are palindromicly amicable if and only if they have the same image by the Parikh matrix mapping. Some other related problems are discussed, too.
متن کاملEfficient text fingerprinting via Parikh mapping
We consider the problem of fingerprinting text by sets of symbols. Specifically, if S is a string, of length n, over a finite, ordered alphabet Σ , and S′ is a substring of S, then the fingerprint of S′ is the subset φ of Σ of precisely the symbols appearing in S′. In this paper we show efficient methods of answering various queries on fingerprint statistics. Our preprocessing is done in time O...
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ژورنال
عنوان ژورنال: RAIRO - Theoretical Informatics and Applications
سال: 2001
ISSN: 0988-3754,1290-385X
DOI: 10.1051/ita:2001131