Arto Salomaa | University of Turku (original) (raw)
Papers by Arto Salomaa
Monographs in Theoretical Computer Science, 2009
Information and Computation/information and Control, 1980
This paper investigates generative grammars with only one type of symbol: no distinction is made ... more This paper investigates generative grammars with only one type of symbol: no distinction is made between terminals and nonterminals. This means that all intermediate words in a derivation are necessarily in the language generated and, consequently, such languages differ considerably from languages generated by grammars, where nonterminals can be used to exclude words from the language. We investigate in this paper basic question concerning language hierarchies, ambiguity and decidability. Also some more general models of pure grammars will be considered.
Birthday ..., 1997
We study a Lindenmayer-like parallel rewriting system to model the growth of filaments (arrays of... more We study a Lindenmayer-like parallel rewriting system to model the growth of filaments (arrays of cells) in which developmental errors may occur. In essence this model is the fuzzy analogue of the derivation-controlled iteration grammar. Under minor assumptions on the family of control languages and on the family of fuzzy languages in the underlying iteration grammar, we show that (i)
We compare the number of states between minimal deterministic ÿnite automata accepting a regular ... more We compare the number of states between minimal deterministic ÿnite automata accepting a regular language and its reversal (mirror image). In the worst case the state complexity of the reversal is 2 n for an n-state language. We present several classes of languages where this maximal blow-up is actually achieved and study the conditions for it. In the case of ÿnite languages the maximal blow-up is not possible but still a surprising variety of di erent growth types can be exhibited.
Theoretical Computer Science, 1998
An insertion grammar is based on pure rules of the form uv → uxv (the string x is inserted in the... more An insertion grammar is based on pure rules of the form uv → uxv (the string x is inserted in the context (u, v)). A strict subfamily of the context-sensitive family is obtained, incomparable with the family of linear languages. We prove here that each recursively enumerable language can be written as the weak coding of the image by an
... There are obvious limits to miniaturization with current computer tech-nologies. ... A typica... more ... There are obvious limits to miniaturization with current computer tech-nologies. ... A typical example would be the cryptanalysis of a ciphertext: all possible keys can be tried ... for computing because, as we will see latter, complementarity brings the universal twin-shuffle language ...
Journal of Experimental and Theoretical Artificial Intelligence, 1995
We consider grammar systems in which several components are active at the same moment (a team of ... more We consider grammar systems in which several components are active at the same moment (a team of components is working). The power of such mechanisms is investigated and it is found that in many cases the team feature increases the generative capacity of grammar systems. In the so-called t-mode of derivation (a team works as much as it can) it
Information and Computation/information and Control - IANDC, 1986
ABSTRACT This work was supported by Natural Science and Engineering Research Council of Canada, G... more ABSTRACT This work was supported by Natural Science and Engineering Research Council of Canada, Grants A7403 and A1617. Most of the work was done while the second and third author were visiting the Computer Science Department of The University of Waterloo.
Theoretical Computer Science, 2007
We investigate factorizations of regular languages in terms of prime languages. A language is sai... more We investigate factorizations of regular languages in terms of prime languages. A language is said to be strongly prime decomposable if any way of factorizing it yields a prime decomposition in a finite number of steps. We give a characterization of the strongly prime decomposable regular languages and using the characterization we show that every regular language over a unary alphabet has a prime decomposition. We show that there exist non-regular unary languages that do not have prime decompositions. We also consider infinite factorizations of unary languages.
Theoretical Computer Science, 1998
We introduce and investigate new methods to define parallel composition of words and languages as... more We introduce and investigate new methods to define parallel composition of words and languages as well as of w-words and o-languages.
Theoretical Computer Science, 1983
Marine Chemistry, 1998
ABSTRACT An automated sampling and analysis system was developed to determine the total inorganic... more ABSTRACT An automated sampling and analysis system was developed to determine the total inorganic carbon (TCO2) in seawater. Measurements are performed on subsamples taken from the shipboard flowing seawater line. The flowing TCO2 system (FTCO2) automatically acidifies and strips the CO2 out of a known volume of sea water and determines the concentration by integrating the infra red (IR) absorbance. Laboratory results have demonstrated an analytical precision of 2–5 μM in TCO2 for this system. Intercomparison of TCO2 measurements with the FTCO2 system and the SOMMA (single operator multimetabolic analyzer) agreed within their respective uncertainties. The TCO2 in surface seawater was determined continually on the flowing seawater line aboard the R/V Thompson in the Arabian Sea. The average difference between the TCO2 determined on surface seawater with the flowing system and the SOMMA was 6.5±8.7 μM. Measurements made with the flowing system on CRMs agreed to ±3 μM with the assigned value. TCO2 in surface waters in the Arabian Sea varied by as much as 40 μM on short spatial and temporal scales. Although the accuracy of the present design of the FTCO2 system is not as good as the SOMMA, the surface TCO2 variability with time and space is captured with the FTCO2 system and is completely missed by discrete measurements made on CTD casts. Continual measurements of TCO2 will be valuable in characterizing the temporal and spatial changes in the carbon dioxide system in surface ocean waters.
Journal of Computer and System Sciences, 2004
Parikh matrices recently introduced give much more information about a word than just the number ... more Parikh matrices recently introduced give much more information about a word than just the number of occurrences of each letter. In this paper we introduce the closely related notion of a subword history and obtain a sequence of general results: elimination of products, decidability of equivalence, and normal form. We also investigate overall methods for proving the validity of such results. A general inequality of ''Cauchy type'' for subword occurrences is established. r
Journal of Computer and System Sciences, 1995
International Journal of Computer Mathematics, 1975
... 185 is a coding of a JTOL language, and a language belongs to EJOL iff it is of the form L n ... more ... 185 is a coding of a JTOL language, and a language belongs to EJOL iff it is of the form L n V,*, for some JOL language L and alphabet V,. (From the defini-tional point of view, EJOL is more natural than JEOL). ... The inclusions EOL E JEOL, EOL G EJOL, EOL G CJOL ...
International Journal of Computer Mathematics, 1994
Starting from the concept of symmetry in algebra and mathematical analysis, we consider the prope... more Starting from the concept of symmetry in algebra and mathematical analysis, we consider the property of a string to remain "unchanged" (member of a given language) by systematicaly interchanging the occurrences of two given symbols. Extensions to sets of symbols, then the symmetric closure and the symmetric kernel of a language are defined and studied, as well as the symmetry of bi-infinite sequences
Monographs in Theoretical Computer Science, 2009
Information and Computation/information and Control, 1980
This paper investigates generative grammars with only one type of symbol: no distinction is made ... more This paper investigates generative grammars with only one type of symbol: no distinction is made between terminals and nonterminals. This means that all intermediate words in a derivation are necessarily in the language generated and, consequently, such languages differ considerably from languages generated by grammars, where nonterminals can be used to exclude words from the language. We investigate in this paper basic question concerning language hierarchies, ambiguity and decidability. Also some more general models of pure grammars will be considered.
Birthday ..., 1997
We study a Lindenmayer-like parallel rewriting system to model the growth of filaments (arrays of... more We study a Lindenmayer-like parallel rewriting system to model the growth of filaments (arrays of cells) in which developmental errors may occur. In essence this model is the fuzzy analogue of the derivation-controlled iteration grammar. Under minor assumptions on the family of control languages and on the family of fuzzy languages in the underlying iteration grammar, we show that (i)
We compare the number of states between minimal deterministic ÿnite automata accepting a regular ... more We compare the number of states between minimal deterministic ÿnite automata accepting a regular language and its reversal (mirror image). In the worst case the state complexity of the reversal is 2 n for an n-state language. We present several classes of languages where this maximal blow-up is actually achieved and study the conditions for it. In the case of ÿnite languages the maximal blow-up is not possible but still a surprising variety of di erent growth types can be exhibited.
Theoretical Computer Science, 1998
An insertion grammar is based on pure rules of the form uv → uxv (the string x is inserted in the... more An insertion grammar is based on pure rules of the form uv → uxv (the string x is inserted in the context (u, v)). A strict subfamily of the context-sensitive family is obtained, incomparable with the family of linear languages. We prove here that each recursively enumerable language can be written as the weak coding of the image by an
... There are obvious limits to miniaturization with current computer tech-nologies. ... A typica... more ... There are obvious limits to miniaturization with current computer tech-nologies. ... A typical example would be the cryptanalysis of a ciphertext: all possible keys can be tried ... for computing because, as we will see latter, complementarity brings the universal twin-shuffle language ...
Journal of Experimental and Theoretical Artificial Intelligence, 1995
We consider grammar systems in which several components are active at the same moment (a team of ... more We consider grammar systems in which several components are active at the same moment (a team of components is working). The power of such mechanisms is investigated and it is found that in many cases the team feature increases the generative capacity of grammar systems. In the so-called t-mode of derivation (a team works as much as it can) it
Information and Computation/information and Control - IANDC, 1986
ABSTRACT This work was supported by Natural Science and Engineering Research Council of Canada, G... more ABSTRACT This work was supported by Natural Science and Engineering Research Council of Canada, Grants A7403 and A1617. Most of the work was done while the second and third author were visiting the Computer Science Department of The University of Waterloo.
Theoretical Computer Science, 2007
We investigate factorizations of regular languages in terms of prime languages. A language is sai... more We investigate factorizations of regular languages in terms of prime languages. A language is said to be strongly prime decomposable if any way of factorizing it yields a prime decomposition in a finite number of steps. We give a characterization of the strongly prime decomposable regular languages and using the characterization we show that every regular language over a unary alphabet has a prime decomposition. We show that there exist non-regular unary languages that do not have prime decompositions. We also consider infinite factorizations of unary languages.
Theoretical Computer Science, 1998
We introduce and investigate new methods to define parallel composition of words and languages as... more We introduce and investigate new methods to define parallel composition of words and languages as well as of w-words and o-languages.
Theoretical Computer Science, 1983
Marine Chemistry, 1998
ABSTRACT An automated sampling and analysis system was developed to determine the total inorganic... more ABSTRACT An automated sampling and analysis system was developed to determine the total inorganic carbon (TCO2) in seawater. Measurements are performed on subsamples taken from the shipboard flowing seawater line. The flowing TCO2 system (FTCO2) automatically acidifies and strips the CO2 out of a known volume of sea water and determines the concentration by integrating the infra red (IR) absorbance. Laboratory results have demonstrated an analytical precision of 2–5 μM in TCO2 for this system. Intercomparison of TCO2 measurements with the FTCO2 system and the SOMMA (single operator multimetabolic analyzer) agreed within their respective uncertainties. The TCO2 in surface seawater was determined continually on the flowing seawater line aboard the R/V Thompson in the Arabian Sea. The average difference between the TCO2 determined on surface seawater with the flowing system and the SOMMA was 6.5±8.7 μM. Measurements made with the flowing system on CRMs agreed to ±3 μM with the assigned value. TCO2 in surface waters in the Arabian Sea varied by as much as 40 μM on short spatial and temporal scales. Although the accuracy of the present design of the FTCO2 system is not as good as the SOMMA, the surface TCO2 variability with time and space is captured with the FTCO2 system and is completely missed by discrete measurements made on CTD casts. Continual measurements of TCO2 will be valuable in characterizing the temporal and spatial changes in the carbon dioxide system in surface ocean waters.
Journal of Computer and System Sciences, 2004
Parikh matrices recently introduced give much more information about a word than just the number ... more Parikh matrices recently introduced give much more information about a word than just the number of occurrences of each letter. In this paper we introduce the closely related notion of a subword history and obtain a sequence of general results: elimination of products, decidability of equivalence, and normal form. We also investigate overall methods for proving the validity of such results. A general inequality of ''Cauchy type'' for subword occurrences is established. r
Journal of Computer and System Sciences, 1995
International Journal of Computer Mathematics, 1975
... 185 is a coding of a JTOL language, and a language belongs to EJOL iff it is of the form L n ... more ... 185 is a coding of a JTOL language, and a language belongs to EJOL iff it is of the form L n V,*, for some JOL language L and alphabet V,. (From the defini-tional point of view, EJOL is more natural than JEOL). ... The inclusions EOL E JEOL, EOL G EJOL, EOL G CJOL ...
International Journal of Computer Mathematics, 1994
Starting from the concept of symmetry in algebra and mathematical analysis, we consider the prope... more Starting from the concept of symmetry in algebra and mathematical analysis, we consider the property of a string to remain "unchanged" (member of a given language) by systematicaly interchanging the occurrences of two given symbols. Extensions to sets of symbols, then the symmetric closure and the symmetric kernel of a language are defined and studied, as well as the symmetry of bi-infinite sequences