Journal articles: 'String classes'

1

Laures, Gerd, and Martin Olbermann. "Cannibalistic classes of string bundles." manuscripta mathematica 156, no. 3-4 (October 4, 2017): 273–98. http://dx.doi.org/10.1007/s00229-017-0978-8.

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Lehtonen, Erkko, Jean-Luc Marichal, and Bruno Teheux. "Associative string functions." Asian-European Journal of Mathematics 07, no. 04 (December 2014): 1450059. http://dx.doi.org/10.1142/s1793557114500594.

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We introduce the concept of associativity for string functions, where a string function is a unary operation on the set of strings over a given alphabet. We discuss this new property and describe certain classes of associative string functions. We also characterize the recently introduced preassociative functions as compositions of associative string functions with injective unary maps. Finally, we provide descriptions of the classes of associative and preassociative functions which depend only on the length of the input.

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Kuribayashi, Katsuhiko. "On the vanishing problem of string classes." Journal of the Australian Mathematical Society. Series A. Pure Mathematics and Statistics 61, no. 2 (October 1996): 258–66. http://dx.doi.org/10.1017/s1446788700000240.

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AbstractThe ordinary string class is an obstruction to lift the structure group LSpin(n) of a loop group bundle LQ → LM to the universal central extension of LSpin(n) by the circle. The vanishing problem of the ordinary string class and generalized string classes are considered from the viewpoint of the ring structure of the cohomology H*(M; R).

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Firmansah, Fery. "ODD HARMONIOUS LABELING ON SOME STRING GRAPH CLASSES." BAREKENG: Jurnal Ilmu Matematika dan Terapan 16, no. 1 (March 21, 2022): 315–22. http://dx.doi.org/10.30598/barekengvol16iss1pp313-320.

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A graph with the labeling properties of odd harmonic is called an odd harmonious graph. The purpose of this research was to get labeling properties of odd harmonic on the class of string graphs. The research used was a qualitative research method. The result of the research was that the definition and construction of a string graph, the union of a string graph, and the multiple string graph are obtained. Furthermore, it has been proved that a string graph, the union of a string graph, and the multiple string graph is an odd harmonious graph.

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DE CAMPOS, JOSÉ EDUARDO PRADO PIRES. "BOUNDARY STRING LINKS." Journal of Knot Theory and Its Ramifications 08, no. 07 (November 1999): 855–78. http://dx.doi.org/10.1142/s0218216599000547.

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The group BSL(k) of boundary cobordism classes of boundary k-string links is defined. An epimorphism from BSL(k) to a group of cobordism classes of matrices is defined. An action of a certain group of pure braids on BSL(k) provides all possible splittings for a given boundary k-link. A necessary and sufficient condition is given for two elements of BSL(k) to have the same closure as an F(k)-link (i.e., a boundary k-link with one of its splittings), up to F(k)-cobordism.

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VOZZO, RAYMOND F. "LOOP GROUPS, STRING CLASSES AND EQUIVARIANT COHOMOLOGY." Journal of the Australian Mathematical Society 90, no. 1 (February 2011): 109–27. http://dx.doi.org/10.1017/s1446788711001066.

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AbstractWe give a classifying theory for LG-bundles, where LG is the loop group of a compact Lie group G, and present a calculation for the string class of the universal LG-bundle. We show that this class is in fact an equivariant cohomology class and give an equivariant differential form representing it. We then use the caloron correspondence to define (higher) characteristic classes for LG-bundles and to prove a result for characteristic classes for based loop groups for the free loop group. These classes have a natural interpretation in equivariant cohomology and we give equivariant differential form representatives for the universal case in all odd dimensions.

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HALPERN, M. B., and C. HELFGOTT. "THE GENERAL TWISTED OPEN WZW STRING." International Journal of Modern Physics A 20, no. 05 (February 20, 2005): 923–92. http://dx.doi.org/10.1142/s0217751x05020628.

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We recently studied two large but disjoint classes of twisted open WZW strings: the open-string sectors of the WZW orientation orbifolds and the so-called basic class of twisted open WZW strings. In this paper, we discuss all T-dualizations of the basic class to construct the general twisted open WZW string — which includes the disjoint classes above as special cases. For the general case, we give the branes and twisted noncommutative geometry at the classical level and the twisted open-string KZ equations at the operator level. Many examples of the general construction are discussed, including in particular the simple case of twisted free-bosonic open strings. We also revisit the open-string sectors of the general WZW orientation orbifold in further detail. For completeness, we finally review the general twisted boundary state equation which provides a complementary description of the general twisted open WZW string.

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Rice, S. V., H. Bunke, and T. A. Nartker. "Classes of cost functions for string edit distance." Algorithmica 18, no. 2 (June 1997): 271–80. http://dx.doi.org/10.1007/bf02526038.

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Becker, Christian. "Cheeger–Chern–Simons Theory and Differential String Classes." Annales Henri Poincaré 17, no. 6 (April 22, 2016): 1529–94. http://dx.doi.org/10.1007/s00023-016-0485-6.

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Konopelchenko, B. G., and G. Landolfi. "On Classical String Configurations." Modern Physics Letters A 12, no. 40 (December 28, 1997): 3161–68. http://dx.doi.org/10.1142/s0217732397003289.

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GÉCSEG, FERENC. "CLASSES OF TREE LANGUAGES DETERMINED BY CLASSES OF MONOIDS." International Journal of Foundations of Computer Science 18, no. 06 (December 2007): 1237–46. http://dx.doi.org/10.1142/s0129054107005285.

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In this paper finite state recognizers are considered as unary tree recognizers with unary operational symbols. We introduce translation recognizers of a tree recognizer, which are finite state recognizers whose operations are the elementary translations of the underlying algebra of the considered tree recognizer. In terms of translation recognizers we give general conditions under which a class of recognizable tree languages with a given property can be determined by a class of monoids determining the class of string languages having the same property.

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Cardoso, G. L., G. Curio, G. Dall'Agata, D. Lüst, P. Manousselis, and G. Zoupanos. "Non-Kähler string backgrounds and their five torsion classes." Nuclear Physics B 652 (March 2003): 5–34. http://dx.doi.org/10.1016/s0550-3213(03)00049-x.

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13

Middendorf, M., and F. Pfeiffer. "The max clique problem in classes of string-graphs." Discrete Mathematics 108, no. 1-3 (October 1992): 365–72. http://dx.doi.org/10.1016/0012-365x(92)90688-c.

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Zeschke, Yorick. "Growth Functions, Rates and Classes of String-Based Multiway Systems." Complex Systems 31, no. 1 (March 15, 2022): 123–64. http://dx.doi.org/10.25088/complexsystems.31.1.123.

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Inspired by the recently emerging Wolfram Physics Project where “Multiway Systems,” graph representations of abstract rewriting systems equipped with a causal structure, have played an important role in discrete models of spacetime and quantum mechanics, this paper establishes several more fundamental properties about the growth (number of states over steps in a system’s evolution) of string rewriting systems in general. While proving the undecidability of exactly determining a system’s growth function, we show several asymptotic properties all growth functions of arbitrary string rewriting systems share. Through an explicit construction, it is proven that string rewriting systems, while never exceeding exponential functions in their growth, are capable of growing arbitrarily slowly, that is, slower than the asymptotic inverse of every Turing-computable function. Additionally, an elementary classification scheme partitioning the set of string rewriting systems into finitely many nontrivial subsets is provided. By introducing arithmetic-like operations under which Multiway Systems form a weakened semiring structure, it is furthermore demonstrated that their growth functions, while always being primitively recursive, can approximate many well-known elementary functions classically used in calculus, which underlines the complexity and computational diversity of Multiway Systems. In the context of the Wolfram Physics Project, some implications of these findings are discussed as well.

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GASPERINI, MAURIZIO. "LOW-ENERGY QUANTUM STRING COSMOLOGY." International Journal of Modern Physics A 13, no. 28 (November 10, 1998): 4779–86. http://dx.doi.org/10.1142/s0217751x98002250.

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We introduce a Wheeler–De Witt approach to quantum cosmology based on the low-energy string effective action, with an effective dilaton potential included to account for nonperturbative effects and, possibly, higher-order corrections. We classify, in particular, four different classes of scattering processes in minisuperspace, and discuss their relevance for the solution of the graceful exit problem.

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GREGOR, JENS, and ERIK GRANUM. "STRING SEGMENTATION AND CLASSIFICATION BY FORCED LANDMARK MARKOV NETWORKS." International Journal of Pattern Recognition and Artificial Intelligence 05, no. 03 (August 1991): 413–23. http://dx.doi.org/10.1142/s0218001491000235.

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A method for segmentation of composite strings into their constituent substrings is presented as an extension to the Markov network inference technique. The basis for the segmentation is forced landmarks which are network representations of the positions where two substrings meet. The landmarks are forced into the Markov model in the inference thereof through supervised labeling. From subsequent string-to-network alignments, it is possible to estimate the positions in the strings that correspond to forced landmarks and thus segment the strings into their substrings. For discrimination between different classes of composite strings, classification probability measures are modified to include model-based information about estimated positions of the landmarks for individual classes. The potential of the method is illustrated with data representing banded human chromosomes.

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Murray, Michael K., and Raymond F. Vozzo. "The caloron correspondence and higher string classes for loop groups." Journal of Geometry and Physics 60, no. 9 (September 2010): 1235–50. http://dx.doi.org/10.1016/j.geomphys.2010.04.010.

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Larraín-Hubach, Andrés, Yoshiaki Maeda, Steven Rosenberg, and Fabián Torres-Ardila. "Equivariant, string and leading order characteristic classes associated to fibrations." Journal of Geometry and Physics 79 (May 2014): 34–52. http://dx.doi.org/10.1016/j.geomphys.2014.01.011.

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19

Day, Joel D., Vijay Ganesh, Nathan Grewal, and Florin Manea. "On the Expressive Power of String Constraints." Proceedings of the ACM on Programming Languages 7, POPL (January 9, 2023): 278–308. http://dx.doi.org/10.1145/3571203.

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We investigate properties of strings which are expressible by canonical types of string constraints. Specifically, we consider a landscape of 20 logical theories, whose syntax is built around combinations of four common elements of string constraints: language membership (e.g. for regular languages), concatenation, equality between string terms, and equality between string-lengths. For a variable x and formula f from a given theory, we consider the set of values for which x may be substituted as part of a satisfying assignment, or in other words, the property f expresses through x. Since we consider string-based logics, this set is a formal language. We firstly consider the relative expressive power of different combinations of string constraints by comparing the classes of languages expressible in the corresponding theories, and are able to establish a mostly complete picture in this regard. Secondly, we consider the question of deciding whether the language or property expressed by a variable/formula in one theory can be expressed in another theory. We establish several negative results which are relevant to preprocessing and normalisation of string constraints in practice. Some of our results have strong connections to important open problems regarding word equations and the theory of string solving.

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Grieser, Diane R., and Karin S. Hendricks. "Review of Literature: Pedagogical Content Knowledge and String Teacher Preparation." Update: Applications of Research in Music Education 37, no. 1 (February 28, 2018): 13–19. http://dx.doi.org/10.1177/8755123318760970.

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In the past few decades, there has been an increase in the percentage of non-string specialists teaching string classes. In this article, we review literature about subject-specific pedagogical content knowledge (PCK) in general and music education settings, to better understand the challenges that teachers with limited knowledge of string-specific content may face when teaching strings students. Included in this review are discussions concerning trends in the string teacher workforce, PCK in education and music, acquisition of PCK in general settings and music teacher preparation programs, and relationships between teacher content knowledge and instructional effectiveness, both in general and string education settings. Based on this review, we recommend that preservice and professional development curricula for music teachers include comprehensive preparation in both content-specific and pedagogical-specific knowledge for teaching strings.

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21

Freund, David R. "Multistring based matrices." Journal of Knot Theory and Its Ramifications 29, no. 06 (May 2020): 2050038. http://dx.doi.org/10.1142/s0218216520500388.

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A virtual[Formula: see text]-string is a chord diagram with [Formula: see text] core circles and a collection of arrows between core circles. We consider virtual [Formula: see text]-strings up to virtual homotopy, compositions of flat virtual Reidemeister moves on chord diagrams. Given a virtual 1-string [Formula: see text], Turaev associated a based matrix that encodes invariants of the virtual homotopy class of [Formula: see text]. We generalize Turaev’s method to associate a multistring based matrix to a virtual [Formula: see text]-string, addressing an open problem of Turaev and constructing similar invariants for virtual homotopy classes of virtual [Formula: see text]-strings.

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HE, YANG-HUI. "AN ALGORITHMIC APPROACH TO STRING PHENOMENOLOGY." Modern Physics Letters A 25, no. 02 (January 20, 2010): 79–90. http://dx.doi.org/10.1142/s0217732310032731.

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We review the recent programme undertaken to construct, systematically and algorithmically, large classes of heterotic vacua, as well as the search for the MSSM therein. Specifically, we outline the monad construction of vector bundles over complete intersection Calabi–Yau threefolds, their classification, stability, equivariant cohomology and subsequent relevance to string phenomenology. It is hoped that this top–down algorithmic approach will isolate special corners in the heterotic landscape.

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Morimae, Tomoyuki, and Harumichi Nishimura. "Merlinization of complexity classes above BQP." Quantum Information and Computation 17, no. 11&12 (September 2017): 959–72. http://dx.doi.org/10.26421/qic17.11-12-3.

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We study how complexity classes above BQP, such as postBQP, postBQPFP, and SBQP, change if we “Merlinize” them, i.e., if we allow an extra input quantum state (or classical bit string) given by Merlin as witness. Our main results are the following: First, the Merlinized version of postBQP is equal to PSPACE. Second, if the Merlinized postBQP is restricted in such a way that the postselection probability is equal for all witness states, then the class is equal to PP. Finally, the Merlinization does not change the class SBQP.

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PĂUN, GHEORGHE, GRZEGORZ ROZENBERG, and TAKASHI YOKOMORI. "HAIRPIN LANGUAGES." International Journal of Foundations of Computer Science 12, no. 06 (December 2001): 837–47. http://dx.doi.org/10.1142/s0129054101000904.

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Molecules with hairpin structure(s) form a natural extension of linear non-branched molecules, and they have been already used in experimental work in DNA computing. In this paper we introduce and investigate classes of string languages (hence languages modeling the sets of linear DNA molecules), consisting of strings which can (fold on itself and) form hairpins. We classify the complexity of these classes using language-theoretic techniques. We also discuss a further use of hairpin molecules in DNA computing.

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JURČO, BRANISLAV. "CROSSED MODULE BUNDLE GERBES; CLASSIFICATION, STRING GROUP AND DIFFERENTIAL GEOMETRY." International Journal of Geometric Methods in Modern Physics 08, no. 05 (August 2011): 1079–95. http://dx.doi.org/10.1142/s0219887811005555.

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We discuss nonabelian bundle gerbes and their differential geometry using simplicial methods. Associated to a (Lie) crossed module (H → D) there is a simplicial group [Formula: see text], the nerve of the groupoid [Formula: see text] defined by the crossed module, and its geometric realization, the topological group [Formula: see text]. We introduce crossed module bundle gerbes so that their (stable) equivalence classes are in a bijection with equivalence classes of principal [Formula: see text]-bundles. We discuss the string group and string structures from this point of view. Also, we give a simplicial interpretation to the bundle gerbe connection and bundle gerbe B-field.

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Akutsu, Taichi. "Constructing a “fast protocol” for middle school beginner violin classes in Japan." International Journal of Music Education 36, no. 1 (February 3, 2017): 96–107. http://dx.doi.org/10.1177/0255761417689918.

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This study aimed to investigate the process of constructing a “fast-protocol” for violin instruction. Since learning string instruments has not been common, and because there are limited hours for music in Japanese schools, the author, a violinist, collaborated with the general music teacher at a middle school in the Tokyo metropolitan area, and co-created the protocol which contains three lesson units as follows: (1) to play an open string on the violin; (2) to discriminate pitch by string crosses on the violin; (3) to discriminate pitch by using fingers on the violin. As for data collection, the study videotaped students’ learning, and maintained log notes. This study also collected students’ commentary focusing on perceived challenges after each class ( N = 120). Based on all gathered data, after completing the coding process, researcher and teacher co-constructed the narrative. Findings include critical examinations of readiness in violin teaching and learning, and variations on violin-specific challenges associated with enjoyment and satisfaction for beginners.

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Madlener, Klaus, and Friedrich Otto. "About the descriptive power of certain classes of finite string-rewriting systems." Theoretical Computer Science 67, no. 2-3 (October 1989): 143–72. http://dx.doi.org/10.1016/0304-3975(89)90002-9.

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Rubin, Sasha. "Automata Presenting Structures: A Survey of the Finite String Case." Bulletin of Symbolic Logic 14, no. 2 (June 2008): 169–209. http://dx.doi.org/10.2178/bsl/1208442827.

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AbstractA structure has a (finite-string)automatic presentationif the elements of its domain can be named by finite strings in such a way that the coded domain and the coded atomic operations are recognised by synchronous multitape automata. Consequently, every structure with an automatic presentation has a decidable first-order theory. The problems surveyed here include the classification of classes of structures with automatic presentations, the complexity of the isomorphism problem, and the relationship between definability and recognisability.

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Laures, Gerd, and Martin Olbermann. "$${ TMF }_0(3)$$ T M F 0 ( 3 ) -Characteristic classes for string bundles." Mathematische Zeitschrift 282, no. 1-2 (November 19, 2015): 511–33. http://dx.doi.org/10.1007/s00209-015-1551-3.

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Belhaj, A., M. Bensed, Z. Benslimane, M. B. Sedra, and A. Segui. "Four-qubit systems and dyonic black Hole–Black branes in superstring theory." International Journal of Geometric Methods in Modern Physics 15, no. 04 (March 13, 2018): 1850065. http://dx.doi.org/10.1142/s0219887818500652.

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Using dyonic solutions in the type IIA superstring theory on Calabi–Yau (CY) manifolds, we reconsider the study of black objects and quantum information theory using string/string duality in six dimensions. Concretely, we relate four-qubits with a stringy quaternionic moduli space of type IIA compactification associated with a dyonic black solution formed by black holes (BHs) and black 2-branes (B2B) carrying eight electric charges and eight magnetic charges. This connection is made by associating the cohomology classes of the heterotic superstring on [Formula: see text] to four-qubit states. These states are interpreted in terms of such dyonic charges resulting from the quaternionic symmetric space [Formula: see text] corresponding to a [Formula: see text] sigma model superpotential in two dimensions. The superpotential is considered as a functional depending on four quaternionic fields mapped to a class of Clifford algebras denoted as [Formula: see text]. A link between such an algebra and the cohomology classes of [Formula: see text] in heterotic superstring theory is also given.

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Schmidt, Margaret. "Preservice String Teachers' Lesson-Planning Processes." Journal of Research in Music Education 53, no. 1 (April 2005): 6–25. http://dx.doi.org/10.1177/002242940505300102.

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This yearlong qualitative study is an examination of 10 undergraduate preservice teachers' lesson planning for the classes and/or individual lessons they taught in a university string project. Data analysis revealed that these preservice teachers held differing views of lesson planning from each other and from their supervisor. Five themes emerged: (a) concerns about knowing how to begin to plan, (b) difficulty identifying what the children needed to learn, (c) the prominence of decisions made on the fly, (d) comparisons of thinking about teaching and planning with actual written plans, and (e) limited transfer of in-class experiences to teaching in the project. Suggestions for teacher educators include acknowledging the complex nonlinear relationship between planning skills, teaching experience, and professional knowledge; structuring guided experiences with a variety of lesson planning formats (e.g., written, mental, verbal); and maximizing opportunities for preservice teachers to reflect on connections between their experiences as students and as teachers. September 22, 2004 December 10, 2004.

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HERRERA-AGUILAR, ALFREDO, and OLEG V. KECHKIN. "STRING THEORY EXTENSIONS OF EINSTEIN–MAXWELL FIELDS: THE STATIC CASE." International Journal of Modern Physics A 17, no. 18 (July 20, 2002): 2485–500. http://dx.doi.org/10.1142/s0217751x02009837.

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We present a new approach for generating solutions in both the four–dimensional heterotic string theory with one vector field and the five–dimensional bosonic string theory, starting from static Einstein–Maxwell fields. Our approach allows one to construct classes of solutions which are invariant with respect to the total subgroup of three-dimensional charging symmetries of these string theories. The new solution-generating procedure leads to the extremal Israel–Wilson–Perjes subclass of string theory solutions in a special case and provides its natural continuous extension to the realm of nonextremal solutions. We explicitly calculate all string theory solutions related to three-dimensional gravity coupled to an effective dilaton field which arises after an appropriate charging symmetry invariant reduction of the static Einstein–Maxwell system.

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Golub, Koraljka, Johan Hagelbäck, and Anders Ardö. "Automatic Classification of Swedish Metadata Using Dewey Decimal Classification: A Comparison of Approaches." Journal of Data and Information Science 5, no. 1 (April 22, 2020): 18–38. http://dx.doi.org/10.2478/jdis-2020-0003.

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AbstractPurposeWith more and more digital collections of various information resources becoming available, also increasing is the challenge of assigning subject index terms and classes from quality knowledge organization systems. While the ultimate purpose is to understand the value of automatically produced Dewey Decimal Classification (DDC) classes for Swedish digital collections, the paper aims to evaluate the performance of six machine learning algorithms as well as a string-matching algorithm based on characteristics of DDC.Design/methodology/approachState-of-the-art machine learning algorithms require at least 1,000 training examples per class. The complete data set at the time of research involved 143,838 records which had to be reduced to top three hierarchical levels of DDC in order to provide sufficient training data (totaling 802 classes in the training and testing sample, out of 14,413 classes at all levels).FindingsEvaluation shows that Support Vector Machine with linear kernel outperforms other machine learning algorithms as well as the string-matching algorithm on average; the string-matching algorithm outperforms machine learning for specific classes when characteristics of DDC are most suitable for the task. Word embeddings combined with different types of neural networks (simple linear network, standard neural network, 1D convolutional neural network, and recurrent neural network) produced worse results than Support Vector Machine, but reach close results, with the benefit of a smaller representation size. Impact of features in machine learning shows that using keywords or combining titles and keywords gives better results than using only titles as input. Stemming only marginally improves the results. Removed stop-words reduced accuracy in most cases, while removing less frequent words increased it marginally. The greatest impact is produced by the number of training examples: 81.90% accuracy on the training set is achieved when at least 1,000 records per class are available in the training set, and 66.13% when too few records (often less than 100 per class) on which to train are available—and these hold only for top 3 hierarchical levels (803 instead of 14,413 classes).Research limitationsHaving to reduce the number of hierarchical levels to top three levels of DDC because of the lack of training data for all classes, skews the results so that they work in experimental conditions but barely for end users in operational retrieval systems.Practical implicationsIn conclusion, for operative information retrieval systems applying purely automatic DDC does not work, either using machine learning (because of the lack of training data for the large number of DDC classes) or using string-matching algorithm (because DDC characteristics perform well for automatic classification only in a small number of classes). Over time, more training examples may become available, and DDC may be enriched with synonyms in order to enhance accuracy of automatic classification which may also benefit information retrieval performance based on DDC. In order for quality information services to reach the objective of highest possible precision and recall, automatic classification should never be implemented on its own; instead, machine-aided indexing that combines the efficiency of automatic suggestions with quality of human decisions at the final stage should be the way for the future.Originality/valueThe study explored machine learning on a large classification system of over 14,000 classes which is used in operational information retrieval systems. Due to lack of sufficient training data across the entire set of classes, an approach complementing machine learning, that of string matching, was applied. This combination should be explored further since it provides the potential for real-life applications with large target classification systems.

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Hopkins, Michael T. "Teachers’ Practices and Beliefs Regarding Teaching Tuning in Elementary and Middle School Group String Classes." Journal of Research in Music Education 61, no. 1 (February 28, 2013): 97–114. http://dx.doi.org/10.1177/0022429412473607.

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The purpose of this study was to examine teachers’ practices and beliefs related to the teaching of stringed instrument tuning in elementary and middle school group classes. The aspects examined included the following: (a) teachers’ beliefs about teaching tuning in their string classes, (b) activities teachers used when teaching tuning in string classes, (c) methods for assessing students’ tuning skills, (d) the grade level that tuning instruction begins, (e) the amount of instructional time used for teaching tuning, (f) teachers’ goals for students’ tuning independence, and (g) teacher, program, or school characteristics that affect how and when tuning is taught. Participants ( N = 139) reported that the average time required to develop tuning independence is 4.5 years. The amount of instructional time available and the level of students’ aural skills were the greatest perceived obstacles to developing tuning independence. Significant differences were found in tuning activities, beliefs about students’ tuning abilities, and assessment procedures and were based on participants’ age, teaching experience, and grade levels taught. The findings indicate a need for further development of tuning pedagogy and greater use of formal assessment to determine if students have developed the prerequisite skills for tuning.

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Middleton, Richard H., and Julio H. Braslavsky. "String Instability in Classes of Linear Time Invariant Formation Control With Limited Communication Range." IEEE Transactions on Automatic Control 55, no. 7 (July 2010): 1519–30. http://dx.doi.org/10.1109/tac.2010.2042318.

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Mishra, Aditya Nath, Dushmanta Sahu, and Raghunath Sahoo. "Jet Transport Coefficient at the Large Hadron Collider Energies in a Color String Percolation Approach." Physics 4, no. 1 (March 16, 2022): 315–28. http://dx.doi.org/10.3390/physics4010022.

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Within the color string percolation model (CSPM), jet transport coefficient, q^, is calculated for various multiplicity classes in proton-proton and centrality classes in nucleus-nucleus collisions at the Large Hadron Collider energies for a better understanding of the matter formed in ultra-relativistic collisions. q^ is studied as a function of final state charged particle multiplicity (pseudorapidity density at midrapidity), initial state percolation temperature and energy density. The CSPM results are then compared with different theoretical calculations from the JET Collaboration those incorporate particle energy loss in the medium.

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Lehrer, G. I. "A toral configuration space and regular semisimple conjugacy classes." Mathematical Proceedings of the Cambridge Philosophical Society 118, no. 1 (July 1995): 105–13. http://dx.doi.org/10.1017/s0305004100073497.

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For any topological space X and integer n ≥ 1, denote by Cn(X) the configuration spaceThe symmetric group Sn acts by permuting coordinates on Cn(X) and we are concerned in this note with the induced graded representation of Sn on the cohomology space H*(Cn(X)) = ⊕iHi (Cn(X), ℂ), where Hi denotes (singular or de Rham) cohomology. When X = ℂ, Cn(X) is a K(π, 1) space, where π is the n-string pure braid group (cf. [3]). The corresponding representation of Sn in this case was determined in [5], using the fact that Cn(C) is a hyperplane complement and a presentation of its cohomology ring appears in [1] and in a more general setting, in [8] (see also [2]).

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SATI, HISHAM. "TWISTED TOPOLOGICAL STRUCTURES RELATED TO M-BRANES II: TWISTED Wu AND Wuc STRUCTURES." International Journal of Geometric Methods in Modern Physics 09, no. 07 (September 7, 2012): 1250056. http://dx.doi.org/10.1142/s0219887812500569.

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Studying the topological aspects of M-branes in M-theory leads to various structures related to Wu classes. First we interpret Wu classes themselves as twisted classes and then define twisted notions of Wu structures. These generalize many known structures, including Pin- structures, twisted Spin structures in the sense of Distler–Freed–Moore, Wu-twisted differential cocycles appearing in the work of Belov–Moore, as well as ones introduced by the author, such as twisted Membrane and twisted String c structures. In addition, we introduce Wu c structures, which generalize Pin c structures, as well as their twisted versions. We show how these structures generalize and encode the usual structures defined via Stiefel–Whitney classes.

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REIS, RUI M. G., RICHARD J. SZABO, and ALESSANDRO VALENTINO. "KO-HOMOLOGY AND TYPE I STRING THEORY." Reviews in Mathematical Physics 21, no. 09 (October 2009): 1091–143. http://dx.doi.org/10.1142/s0129055x09003839.

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We study the classification of D-branes and Ramond–Ramond fields in Type I string theory by developing a geometric description of KO-homology. We define an analytic version of KO-homology using KK-theory of real C*-algebras, and construct explicitly the isomorphism between geometric and analytic KO-homology. The construction involves recasting the C ℓn-index theorem and a certain geometric invariant into a homological framework which is used, along with a definition of the real Chern character in KO-homology, to derive cohomological index formulas. We show that this invariant also naturally assigns torsion charges to non-BPS states in Type I string theory, in the construction of classes of D-branes in terms of topological KO-cycles. The formalism naturally captures the coupling of Ramond–Ramond fields to background D-branes which cancel global anomalies in the string theory path integral. We show that this is related to a physical interpretation of bivariant KK-theory in terms of decay processes on spacetime-filling branes. We also provide a construction of the holonomies of Ramond–Ramond fields in Type II string theory in terms of topological K-chains.

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Alves, Edenise Segala, Eduardo Luiz Longui, and Erika Amano. "Pernambuco Wood (Caesalpinia Echinata) used in the Manufacture of Bows for String Instruments." IAWA Journal 29, no. 3 (2008): 323–35. http://dx.doi.org/10.1163/22941932-90000190.

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The anatomy and the physical, mechanical, acoustical and chemical properties of pernambuco wood (Caesalpinia echinata Lam.) were investigated to determine factors that could explain the different quality of sticks used in bow manufacture. Eighteen sticks were classified into four classes (A to D with A being the best) according to their potential quality for bow manufacture. Selection of samples was based on the experience of a bow maker and on some nondestructive tests. The A-class sticks had a lower frequency of vessels and rays and a higher percentage of fibers when compared to the other classes. They also had higher values of density, speed of sound propagation, modulus of elasticity and modulus of rupture. Klason lignin content was higher in the A-class sticks but the quantity of hydrosoluble and ethanol/benzene soluble extractives was lower. The values of density and speed of sound propagation obtained by nondestructive and destructive methods were similar showing the applicability of the former in the prior selection process of the sticks.

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Sabri, Shafizan Bin. "Implication of an Objectivist-Constructivist Blended Approach on Students’ Achievement and Satisfaction in University-Level Beginner String Technique Classes." Journal of Education and Culture Studies 2, no. 3 (August 10, 2018): 173. http://dx.doi.org/10.22158/jecs.v2n3p173.

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<p><em>Teaching music generally implicates multidimensional process whereby an assortment of approaches should be incorporated in order to provide the right and proper ambience for teaching and learning process. The need to explore and further understand the complexity in teaching beginner string technique class instigates the study which explore the implication of an objectivist-constructivist blended approach for teaching beginners string technique class. This paper explores the impact of blended-approach teaching on students’ achievement and satisfaction in Malaysian university-level beginner string technique classes. Using a quasi-experimental non-equivalent control group post-test only design, students (N = 40) from two local public universities were assigned to one of two treatment condition: experimental group, where students were presented with blended approach instructional material, and control group, where students were presented with conventional instructional material. Students completed the course of 14 weeks. The implementation results revealed that the proposed blended approach contributes to meaningful and efficient learning.</em></p>

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SATI, HISHAM, URS SCHREIBER, and JIM STASHEFF. "FIVEBRANE STRUCTURES." Reviews in Mathematical Physics 21, no. 10 (November 2009): 1197–240. http://dx.doi.org/10.1142/s0129055x09003840.

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We study the cohomological physics of fivebranes in type II and heterotic string theory. We give an interpretation of the one-loop term in type IIA, which involves the first and second Pontrjagin classes of spacetime, in terms of obstructions to having bundles with certain structure groups. Using a generalization of the Green–Schwarz anomaly cancellation in heterotic string theory which demands the target space to have a String structure, we observe that the "magnetic dual" version of the anomaly cancellation condition can be read as a higher analog of String structure, which we call Fivebrane structure. This involves lifts of orthogonal and unitary structures through higher connected covers which are not just 3- but even 7-connected. We discuss the topological obstructions to the existence of Fivebrane structures. The dual version of the anomaly cancellation points to a relation of string and Fivebrane structures under electric-magnetic duality.

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Blumenhagen, Ralph, Benjamin Jurke, and Thorsten Rahn. "Computational Tools for Cohomology of Toric Varieties." Advances in High Energy Physics 2011 (2011): 1–15. http://dx.doi.org/10.1155/2011/152749.

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Novel nonstandard techniques for the computation of cohomology classes on toric varieties are summarized. After an introduction of the basic definitions and properties of toric geometry, we discuss a specific computational algorithm for the determination of the dimension of line-bundle-valued cohomology groups on toric varieties. Applications to the computation of chiral massless matter spectra in string compactifications are discussed, and using the software packagecohomCalg, its utility is highlighted on a new target space dual pair of(0,2)heterotic string models.

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CHEN, GANG. "SPECTRAL FLOW AND FREE FIELD REALIZATIONS OF BOSONIC STRINGS ON NAPPI–WITTEN GROUP MANIFOLD." International Journal of Modern Physics A 26, no. 01 (January 10, 2011): 149–60. http://dx.doi.org/10.1142/s0217751x1105141x.

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In this paper we study some aspects of closed string theories in the Nappi–Witten space–time. The effects of spectral flow on the geodesics are studied in terms of an explicit parametrization of the group manifold. The worldsheets of the closed strings under the spectral flow of the geodesics can be classified into four classes, each with a geometric interpretation. We also obtain a free field realization of the Nappi–Witten affine Lie algebra in the most general conditions using a different but equivalent parametrization of the group manifold.

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BELLUCCI, STEFANO, and BHUPENDRA NATH TIWARI. "BLACK STRINGS, BLACK RINGS AND STATE-SPACE MANIFOLD." International Journal of Modern Physics A 26, no. 32 (December 30, 2011): 5403–64. http://dx.doi.org/10.1142/s0217751x11054978.

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State-space geometry is considered, for diverse three and four parameter nonspherical horizon rotating black brane configurations, in string theory and M-theory. We have explicitly examined the case of unit Kaluza–Klein momentum D1D5P black strings, circular strings, small black rings and black supertubes. An investigation of the state-space pair correlation functions shows that there exist two classes of brane statistical configurations, viz. the first category divulges a degenerate intrinsic equilibrium basis, while the second yields a nondegenerate, curved, intrinsic Riemannian geometry. Specifically, the solutions with finitely many branes expose that the two charged rotating D1D5 black strings and three charged rotating small black rings consort real degenerate state-space manifolds. Interestingly, arbitrary valued M5-dipole charged rotating circular strings and Maldacena–Strominger–Witten black rings exhibit nondegenerate, positively curved, comprehensively regular state-space configurations. Furthermore, the state-space geometry of single bubbled rings admits a well-defined, positive definite, everywhere regular and curved intrinsic Riemannian manifold; except for the two finite values of conserved electric charge. We also discuss the implication and potential significance of this work for the physics of black holes in string theory.

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Fernau, Henning, Lakshmanan Kuppusamy, and Indhumathi Raman. "On describing the regular closure of the linear languages with graph-controlled insertion-deletion systems." RAIRO - Theoretical Informatics and Applications 52, no. 1 (January 2018): 1–21. http://dx.doi.org/10.1051/ita/2018005.

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A graph-controlled insertion-deletion (GCID) system has several components and each component contains some insertion-deletion rules. A transition is performed by any applicable rule in the current component on a string and the resultant string is then moved to the target component specified in the rule. The language of the system is the set of all terminal strings collected in the final component. When resources are very limited (especially, when deletion is demanded to be context-free and insertion to be one-sided only), then GCID systems are not known to describe the class of recursively enumerable languages. Hence, it becomes interesting to explore the descriptional complexity of such GCID systems of small sizes with respect to language classes below RE and even below CF. To this end, we consider so-called closure classes of linear languages defined over the operations concatenation, Kleene star and union. We show that whenever GCID systems (with certain syntactical restrictions) describe all linear languages (LIN) with t components, we can extend this to GCID systems with just one more component to describe, for instance, the concatenation of two languages from the language family that can be described as the Kleene closure of linear languages. With further addition of one more component, we can extend the construction to GCID systems that describe the regular closure of LIN.

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LÜ, H., S. MUKHERJI, and C. N. POPE. "FROM p-BRANES TO COSMOLOGY." International Journal of Modern Physics A 14, no. 26 (October 20, 1999): 4121–42. http://dx.doi.org/10.1142/s0217751x99001925.

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We study the relationship between static p-brane solitons and cosmological solutions of string theory or M theory. We discuss two different ways in which extremal p-branes can be generalized to nonextremal ones, and show how wide classes of recently discussed cosmological models can be mapped into nonextremal p-brane solutions of one of these two kinds. We also extend previous discussions of cosmological solutions to include some that make use of cosmological-type terms in the effective action that can arise from the generalized dimensional reduction of string theory or M theory.

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Khachatryan, Kh A. "On the solubility of certain classes of non-linear integral equations in $ p$-adic string theory." Izvestiya: Mathematics 82, no. 2 (April 26, 2018): 407–27. http://dx.doi.org/10.1070/im8580.

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Eom, Hwajin, and Wontae Kim. "Analytic approach to the formation of a three-dimensional black string from a dust cloud." Journal of Cosmology and Astroparticle Physics 2022, no. 11 (November 1, 2022): 004. http://dx.doi.org/10.1088/1475-7516/2022/11/004.

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Abstract In three-dimensional low-energy string theory, we study the formation of a black string from a dust cloud. We analytically obtain two distinct classes of exact solutions with arbitrary functions responsible for mass distributions of the dust cloud. The first and second kinds of solutions may describe collapsing dusts but the first kind is only for inhomogeneous dust distribution while the second kind has a homogeneous limit. The finite collapse time and the Israel junction conditions tell us that the first kind solution describes a desired collapsing phenomenon, whereas the scale factor in the inner spacetime for the second kind turns out to be trivial. In the first kind solution, specific collapsing models can be realized by choosing an appropriate inhomogeneous dust distribution consistent with the Israel junction conditions. Consequently, the inhomogeneous dust cloud eventually collapses to the black string although the homogeneous dust cloud does not guarantee the formation of the black string in our setting. The space-like curvature singularities occur at the finite collapse time and they can be cloaked by the horizon of the black string.

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Songhafouo Tsopméné, Paul Arnaud, and Victor Turchin. "Rational homology and homotopy of high-dimensional string links." Forum Mathematicum 30, no. 5 (September 1, 2018): 1209–35. http://dx.doi.org/10.1515/forum-2016-0192.

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AbstractArone and the second author showed that when the dimensions are in the stable range, the rational homology and homotopy of the high-dimensional analogues of spaces of long knots can be calculated as the homology of a direct sum of finite graph-complexes that they described explicitly. They also showed that these homology and homotopy groups can be interpreted as the higher-order Hochschild homology, also called Hochschild–Pirashvili homology. In this paper, we generalize all these results to high-dimensional analogues of spaces of string links. The methods of our paper are applicable in the range when the ambient dimension is at least twice the maximal dimension of a link component plus two, which in particular guarantees that the spaces under study are connected. However, we conjecture that our homotopy graph-complex computes the rational homotopy groups of link spaces always when the codimension is greater than two, i.e. always when the Goodwillie–Weiss calculus is applicable. Using Haefliger’s approach to calculate the groups of isotopy classes of higher-dimensional links, we confirm our conjecture at the level of {\pi_{0}}.

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Journal articles on the topic 'String classes'

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