{"title":"Parameterizing higher-order processes on names and processes","authors":"Xian Xu","doi":"10.1051/ita/2019005","DOIUrl":"https://doi.org/10.1051/ita/2019005","url":null,"abstract":"Parameterization extends higher-order processes with the capability of abstraction and application (like those in lambda-calculus). As is well-known, this extension is strict, meaning that higher-order processes equipped with parameterization are strictly more expressive than those without parameterization. This paper studies strictly higher-order processes (i.e., no name-passing) with two kinds of parameterization: one on names and the other on processes themselves. We present two main results. One is that in presence of parameterization, higher-order processes can interpret first-order (name-passing) processes in a quite elegant fashion, in contrast to the fact that higher-order processes without parameterization cannot encode first-order processes at all. We present two such encodings and analyze their properties in depth, particularly full abstraction. In the other result, we provide a simpler characterization of the standard context bisimilarity for higher-order processes with parameterization, in terms of the normal bisimilarity that stems from the well-known normal characterization for higher-order calculus. As a spinoff, we show that the bisimulation up-to context technique is sound in the higher-order setting with parameterization.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"185 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116405651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the length of uncompletable words in unambiguous automata","authors":"A. Boccuto, A. Carpi","doi":"10.1051/ITA/2019002","DOIUrl":"https://doi.org/10.1051/ITA/2019002","url":null,"abstract":"This paper deals with uncomplete unambiguous automata. In this setting, we investigate the minimal length of uncompletable words. This problem is connected with a well-known conjecture formulated by A. Restivo. We introduce the notion of relatively maximal row for a suitable monoid of matrices. We show that, if M is a monoid of {0, 1}-matrices of dimension n generated by a set S, then there is a matrix of M containing a relatively maximal row which can be expressed as a product of O(n3) matrices of S. As an application, we derive some upper bound to the minimal length of an uncompletable word of an uncomplete unambiguous automaton, in the case that its transformation monoid contains a relatively maximal row which is not maximal. Finally we introduce the maximal row automaton associated with an unambiguous automaton A. It is a deterministic automaton, which is complete if and only if A is. We prove that the minimal length of the uncompletable words of A is polynomially bounded by the number of states of A and the minimal length of the uncompletable words of the associated maximal row automaton.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116142321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the power of two-way multihead quantum finite automata","authors":"A. Bhatia, Ajay Kumar","doi":"10.1051/ita/2018020","DOIUrl":"https://doi.org/10.1051/ita/2018020","url":null,"abstract":"This paper introduces a variant of two-way quantum finite automata named two-way multihead quantum finite automata. A two-way quantum finite automaton is more powerful than classical two-way finite automata. However, the generalizations of two-way quantum finite automata have not been defined so far as compared to one-way quantum finite automata model. We have investigated the newly introduced automata from two aspects: the language recognition capability and its comparison with classical and quantum counterparts. It has been proved that a language which cannot be recognized by any one-way and multi-letter quantum finite automata can be recognized by two-way quantum finite automata. Further, it has been shown that a language which cannot be recognized by two-way quantum finite automata can be recognized by two-way multihead quantum finite automata with two heads. Furthermore, it has been investigated that quantum variant of two-way deterministic multihead finite automata takes less number of heads to recognize a language containing of all words whose length is a prime number.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115189590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An efficient certificateless multi-receiver threshold decryption scheme","authors":"Ronghai Gao, Jiwen Zeng, Lunzhi Deng","doi":"10.1051/ita/2019001","DOIUrl":"https://doi.org/10.1051/ita/2019001","url":null,"abstract":"Threshold decryption allows only quorum cooperate users to decrypt ciphertext encrypted under a public key. However, such threshold decryption scheme cannot be applied well in this situation where all users have their public and private key pairs, but do not share any private keys corresponding to the public keys, such as mobile network featured with dynamic character. The direct way to achieve threshold decryption in this case is to divide the message into several pieces and then encrypt these pieces with the public keys of different users. However, this is very inefficient. Multireceiver threshold decryption scheme that could be applied efficiently in the above situation. Recently, some certificateless (ID-based) multireceiver threshold decryption (signcryption) schemes are introduced. But the bilinear pairings are used in most of the existing schemes. In this paper, we propose an efficient certificateless threshold decryption scheme using elliptic curve cryptography (ECC) without bilinear pairing. Performance analysis shows that the proposed scheme has lower computation cost than existing some threshold decryption schemes in both encryption and decryption process. Security analysis shows that our scheme is IND-CCA secure, and no one outside of selected receivers can disclose receivers identities, against the adversaries defined in CL-PKC system under the random oracle model.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130774691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Derived sequences of complementary symmetric Rote sequences","authors":"K. Medková, E. Pelantov'a, L. Vuillon","doi":"10.1051/ita/2019004","DOIUrl":"https://doi.org/10.1051/ita/2019004","url":null,"abstract":"Complementary symmetric Rote sequences are binary sequences which have factor complexity C(n) = 2n for all integers n ≥ 1 and whose languages are closed under the exchange of letters. These sequences are intimately linked to Sturmian sequences. Using this connection we investigate the return words and the derived sequences to the prefixes of any complementary symmetric Rote sequence v which is associated with a standard Sturmian sequence u. We show that any non-empty prefix of v has three return words. We prove that any derived sequence of v is coding of three interval exchange transformation and we determine the parameters of this transformation. We also prove that v is primitive substitutive if and only if u is primitive substitutive. Moreover, if the sequence u is a fixed point of a primitive morphism, then all derived sequences of v are also fixed by primitive morphisms. In that case we provide an algorithm for finding these fixing morphisms.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114417868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Avoiding conjugacy classes on the 5-letter alphabet","authors":"Golnaz Badkobeh, Pascal Ochem","doi":"10.1051/ita/2020003","DOIUrl":"https://doi.org/10.1051/ita/2020003","url":null,"abstract":"We construct an infinite word w over the 5-letter alphabet such that for every factor f of w of length at least two, there exists a cyclic permutation of f that is not a factor of w. In other words, w does not contain a non-trivial conjugacy class. This proves the conjecture in Gamard et al. [Theoret. Comput. Sci. 726 (2018) 1–4].","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117320359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The complexity of weakly recognizing morphisms","authors":"Lukas Fleischer, Manfred Kufleitner","doi":"10.1051/ita/2018006","DOIUrl":"https://doi.org/10.1051/ita/2018006","url":null,"abstract":"Weakly recognizing morphisms from free semigroups onto finite semigroups are a classical way for defining the class of ω-regular languages, i.e., a set of infinite words is weakly recognizable by such a morphism if and only if it is accepted by some Büchi automaton. We study the descriptional complexity of various constructions and the computational complexity of various decision problems for weakly recognizing morphisms. The constructions we consider are the conversion from and to Büchi automata, the conversion into strongly recognizing morphisms, as well as complementation. We also show that the fixed membership problem is NC1-complete, the general membership problem is in L and that the inclusion, equivalence and universality problems are NL-complete. The emptiness problem is shown to be NL-complete if the input is given as a non-surjective morphism.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114968397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Upper bound for palindromic and factor complexity of rich words","authors":"Josef Rukavicka","doi":"10.1051/ITA/2020008","DOIUrl":"https://doi.org/10.1051/ITA/2020008","url":null,"abstract":"A finite word w of length n contains at most n + 1 distinct palindromic factors. If the bound n + 1 is attained, the word w is called rich. An infinite word w is called rich if every finite factor of w is rich.\u0000\u0000Let w be a word (finite or infinite) over an alphabet with q > 1 letters, let Facw(n) be the set of factors of length n of the word w, and let Palw(n) ⊆ Facw(n) be the set of palindromic factors of length n of the word w.\u0000\u0000We present several upper bounds for |Facw(n)| and |Palw(n)|, where w is a rich word. Let δ = [see formula in PDF]. In particular we show that\u0000\u0000|Facw(n)| ≤ (4q2n)δ ln 2n+2.\u0000\u0000In 2007, Baláži, Masáková, and Pelantová showed that\u0000\u0000|Palw(n)|+|Palw(n+1)| ≤ |Facw(n+1)|-|Facw(n)|+2,\u0000\u0000where w is an infinite word whose set of factors is closed under reversal. We prove this inequality for every finite word v with |v| ≥ n + 1 and v(n + 1) closed under reversal.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114973321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Regular and linear permutation languages","authors":"G. Madejski","doi":"10.1051/ita/2018016","DOIUrl":"https://doi.org/10.1051/ita/2018016","url":null,"abstract":"A permutation rule is a non-context-free rule whose both sides contain the same multiset of symbols with at least one non-terminal. This rule does not add or substitute any symbols in the sentential form, but can be used to change the order of neighbouring symbols. In this paper, we consider regular and linear grammars extended with permutation rules. It is established that the generative power of these grammars relies not only on the length of the permutation rules, but also whether we allow or forbid the usage of erasing rules. This is quite surprising, since there is only one non-terminal in sentential forms of derivations for regular or linear grammars. Some decidability problems and closure properties of the generated families of languages are investigated. We also show a link to a similar model which mixes the symbols: grammars with jumping derivation mode.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131249205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On double-jumping finite automata and their closure properties","authors":"Radim Kocman, Z. Křivka, A. Meduna","doi":"10.1051/ita/2018013","DOIUrl":"https://doi.org/10.1051/ita/2018013","url":null,"abstract":"The present paper modifies and studies jumping finite automata so they always perform two simultaneous jumps according to the same rule. For either of the two simultaneous jumps, it considers three natural directions – (1) to the left, (2) to the right, and (3) in either direction. According to this jumping-direction three-part classification, the paper investigates the mutual relation between the language families resulting from jumping finite automata performing the jumps in these ways and the families of regular, linear, context-free, and context-sensitive languages. It demonstrates that most of these language families are pairwise incomparable. In addition, many closure and non-closure properties of the resulting language families are established.","PeriodicalId":438841,"journal":{"name":"RAIRO Theor. Informatics Appl.","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116267040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}