The Experts below are selected from a list of 3853767 Experts worldwide ranked by ideXlab platform
Hiroyuki Seki - One of the best experts on this subject based on the ideXlab platform.
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layered transducing term rewriting system and its Recognizability preserving property
Lecture Notes in Computer Science, 2002Co-Authors: Hiroyuki Seki, Toshinori Takai, Youhei Fujinaka, Yuichi KajiAbstract:A term rewriting system which effectively preserves Recognizability (EPR-TRS) has good mathematical properties. In this paper, a new subclass of TRSs, layered transducing TRSs (LT-TRSs) is defined and its Recognizability preserving property is discussed. The class of LT-TRSs contains some EPR-TRSs, e.g., {f(x) → f(g(x))} which do not belong to any of the known decidable subclasses of EPR-TRSs. Bottom-up linear tree transducer, which is a well-known computation model in the tree language theory, is a special case of LT-TRS. We present a sufficient condition for an LT-TRS to be an EPR-TRS. Also some properties of LT-TRSs including reachability are shown to be decidable.
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right linear finite path overlapping term rewriting systems effectively preserve Recognizability
Rewriting Techniques and Applications, 2000Co-Authors: Toshinori Takai, Yuichi Kaji, Hiroyuki SekiAbstract:Right-linear finite path overlapping TRS are shown to effectively preserve Recognizability. The class of right-linear finite path overlapping TRS properly includes the class of linear generalized semi-monadic TRS and the class of inverse left-linear growing TRS, which are known to effectively preserve Recognizability. Approximations by inverse right-linear finite path overlapping TRS are also discussed.
Yuichi Kaji - One of the best experts on this subject based on the ideXlab platform.
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layered transducing term rewriting system and its Recognizability preserving property
Lecture Notes in Computer Science, 2002Co-Authors: Hiroyuki Seki, Toshinori Takai, Youhei Fujinaka, Yuichi KajiAbstract:A term rewriting system which effectively preserves Recognizability (EPR-TRS) has good mathematical properties. In this paper, a new subclass of TRSs, layered transducing TRSs (LT-TRSs) is defined and its Recognizability preserving property is discussed. The class of LT-TRSs contains some EPR-TRSs, e.g., {f(x) → f(g(x))} which do not belong to any of the known decidable subclasses of EPR-TRSs. Bottom-up linear tree transducer, which is a well-known computation model in the tree language theory, is a special case of LT-TRS. We present a sufficient condition for an LT-TRS to be an EPR-TRS. Also some properties of LT-TRSs including reachability are shown to be decidable.
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right linear finite path overlapping term rewriting systems effectively preserve Recognizability
Rewriting Techniques and Applications, 2000Co-Authors: Toshinori Takai, Yuichi Kaji, Hiroyuki SekiAbstract:Right-linear finite path overlapping TRS are shown to effectively preserve Recognizability. The class of right-linear finite path overlapping TRS properly includes the class of linear generalized semi-monadic TRS and the class of inverse left-linear growing TRS, which are known to effectively preserve Recognizability. Approximations by inverse right-linear finite path overlapping TRS are also discussed.
Andreas Maletti - One of the best experts on this subject based on the ideXlab platform.
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preservation of Recognizability for synchronous tree substitution grammars
Meeting of the Association for Computational Linguistics, 2010Co-Authors: Zoltan Fulop, Andreas Maletti, Heiko VoglerAbstract:We consider synchronous tree substitution grammars (Stsg). With the help of a characterization of the expressive power of Stsg in terms of weighted tree bimorphisms, we show that both the forward and the backward application of an Stsg preserve Recognizability of weighted tree languages in all reasonable cases. As a consequence, both the domain and the range of an Stsg without chain rules are recognizable weighted tree languages.
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does o substitution preserve Recognizability
Lecture Notes in Computer Science, 2006Co-Authors: Andreas MalettiAbstract:Substitution operations on tree series are at the basis of systems of equations (over tree series) and tree series transducers. Tree series transducers seem to be an interesting transformation device in syntactic pattern matching. In this contribution, it is shown that o-substitution preserves recognizable tree series provided that the target tree series is linear and the semiring is idempotent, commutative, and continuous. This result is applied to prove that the range of the o-t-ts transformation computed by a linear recognizable tree series transducer is pointwise recognizable.
Ilya Gorshkov - One of the best experts on this subject based on the ideXlab platform.
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Recognizability of symmetric groups by spectrum
Algebra and Logic, 2015Co-Authors: Ilya GorshkovAbstract:The spectrum of a finite group is the set of its element orders. A finite group G is said to be recognizable by spectrum if every finite group whose spectrum coincides with the spectrum of G is isomorphic to G. It is proved the symmetric group S n is recognizable by spectrum for n ∉ {2, 3, 4, 5, 6, 8, 10, 15, 16, 18, 21, 27, 33, 35, 39, 45}.
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Recognizability of alternating groups by spectrum
Algebra and Logic, 2013Co-Authors: Ilya GorshkovAbstract:The spectrum of a group is the set of its element orders. A finite group G is said to be recognizable by spectrum if every finite group that has the same spectrum as G is isomorphic to G. It is proved that simple alternating groups A n are recognizable by spectrum, for n ≠ 6, 10. This implies that every finite group whose spectrum coincides with that of a finite non-Abelian simple group has at most one non-Abelian composition factor.
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on Recognizability by spectrum of finite simple groups of types bn cn and 2dn for n 2k
Proceedings of the Steklov Institute of Mathematics, 2009Co-Authors: A V Vasilev, Ilya Gorshkov, M A Grechkoseeva, A S Kondratev, Alexey StaroletovAbstract:The spectrum of a finite group is the set of its element orders. A group is said to be recognizable (by spectrum) if it is isomorphic to any finite group that has the same spectrum. A nonabelian simple group is called quasi-recognizable if every finite group with the same spectrum possesses a unique nonabelian composition factor and this factor is isomorphic to the simple group in question. We consider the problem of Recognizability and quasi-Recognizability for finite simple groups of types Bn, Cn, and 2Dn with n = 2k.
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on recognition of finite simple groups with connected prime graph
Siberian Mathematical Journal, 2009Co-Authors: A V Vasilev, Ilya GorshkovAbstract:The spectrum of a finite group is the set of its element orders. We prove a theorem on the structure of a finite group whose spectrum is equal to the spectrum of a finite nonabelian simple group. The theorem can be applied to solving the problem of Recognizability of finite simple groups by spectrum.
Guo-qiang Zhang - One of the best experts on this subject based on the ideXlab platform.
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On transformations of formal power series
Information & Computation, 2003Co-Authors: Manfred Droste, Guo-qiang ZhangAbstract:Formal power series are an extension of formal languages. Recognizable formal power series can be captured by the so-called weighted finite automata, generalizing finite state machines. In this paper, motivated by codings of formal languages, we introduce and investigate two types of transformations for formal power series. We characterize when these transformations preserve Recognizability, generalizing the recent results of Zhang [16] to the formal power series setting. We show, for example, that the "square-root" operation, while preserving regularity for formal languages, preserves Recognizability for formal power series when the underlying semiring is commutative or locally finite, but not in general.