Results 1 to 10 of about 18,006 (157)
Singular finite-gap operators and indefinite metrics [PDF]
Russian Mathematical Surveys, 2009 LaTex, 30 pages In the updated version: 3 references added, extensions of the x-space with indefinite metric and the analysis of the Lame potentials are described in more details, relations with Crum transformations are discussed. Discussion of degenerate cases (hyperbolic and trigonometric) and Crum-Darboux transformations is added.
Grinevich, P., Novikov, S.
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Journal of Function Spaces, 2018 In this paper, a class of indefinite hypersurfaces and a class of indefinite surfaces generated by timelike curves located in nullcone in 4-dimensional semi-Euclidean space with index 2 are discussed. Using the unfolding theory in singularity theory, the
Xue Song, Zhigang Wang
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Singular soliton operators and indefinite metrics [PDF]
Bulletin of the Brazilian Mathematical Society, New Series, 2013 LaTex, 34 pages, 3 figures. Some references were corrected. Additional results about decomposition by eigenfunctions of complex singular finite-gap potentials, higher order potentials and non-statiobnary Schrodinger operator were ...
Grinevich, Petr G., Novikov, Sergey P.
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Singularities of discrete improper indefinite affine spheres
Journal of Geometry, 2023 We consider in this paper discrete improper affine spheres based on asymptotic nets. In this context, we distinguish the discrete edges and vertices that must be considered singular. The singular edges can be considered as discrete cuspidal edges, while some of the singular vertices can be considered as discrete swallowtails.
de Vargas, Anderson Reis +1 more
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An exact expression of positive periodic solution for a first-order singular equation
Advances in Difference Equations, 2020 The main purpose of this paper is to obtain an exact expression of the positive periodic solution for a first-order differential equation with attractive and repulsive singularities.
Yun Xin, Xiaoxiao Cui, Jie Liu
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Semantic Incorporation in English Singular Indefinites
Journal of Semantics, 2023 Abstract In this paper, we introduce a class of exceptionally narrow-scoping singular indefinites in English (e.g., “Sam drove a car for several years before switching to a truck”), which pattern more closely with what have been termed “weak definites” in the literature (e.g., Poesio, 1994; Carlson et al., 2006) than with regular ...
Sadhwi Srinivas, Kyle Rawlins
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Electronic Journal of Qualitative Theory of Differential Equations, 2020 We establish the existence of positive solutions for the singular quasilinear Schrödinger equation \begin{equation*} \begin{cases} -\Delta u -\Delta (u^{2})u=h(x) u^{-\gamma} + f(x,u)& \mbox{in } \Omega,\\ u(x)=0&\mbox{on }\partial \Omega, \end{cases ...
Ricardo Alves, Mariana Reis
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General radially moving references frames in the black hole background
European Physical Journal C: Particles and Fields, 2023 We consider general radially moving frames realized in the background of nonextremal black holes having causal structure similar to that of the Schwarzschild metric. In doing so, we generalize the Lemaître approach, constructing free-falling frames which
A. V. Toporensky, O. B. Zaslavskii
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Indefinite LQ Problem for Irregular Singular Systems [PDF]
Mathematical Problems in Engineering, 2014 The indefinite LQ problem for irregular singular systems is investigated. Under some general conditions, the optimal control‐state pair is obtained by solving an algebraic Riccati equation. The optimal control is synthesized as state feedback. All the finite poles of the closed‐loop system are located on the left‐half complex plane. An example is given
Qingxiang Fang, Jigen Peng, Feilong Cao
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The pronominal system of Odual
Studies in African Linguistics, 2007 This paper discusses the pronominal system of Odual, which has five subsets of pronouns: personal, reflexive, interrogative, demonstrative, and indefinite. A noteworthy feature of the system is the distinction between inclusive and exclusive first person
Ethelbert E. Kari
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