45,874 research outputs found
On the construction of partial difference schemes I: the Clairaut, Schwarz, Young theorem on the lattice
No full textLie symmetries for integrable evolution equations on the lattice
No full textIn this work we show how to construct symmetries for the differential-difference equations associated with the discrete Schrodinger spectral problem. We find the whole set of symmetries which in the continuous limit go into the Lie point symmetries of the corresponding partial differential equation, i.e, the Korteweg-de Vries equation. Among these, of particular relevance, is the non-autonomous symmetry which, in the continuous limit, goes into the dilation symmetry for the corresponding equation. Unlike the continuous case, this symmetry turns out to be a master symmetry, thus belonging to the infinite-dimensional group of generalized symmetries
SYMMETRY GROUP OF PARTIAL-DIFFERENTIAL EQUATIONS AND OF DIFFERENTIAL DIFFERENCE-EQUATIONS - THE TODA LATTICE VERSUS THE KORTEWEG-DEVRIES EQUATION
No full textIn this work we correlate the symmetry group of the continuous transformations of the Toda lattice to that of the Korteweg-de Vries equation. We show how, by taking into account the continuous limit of the Toda, the four-parameter symmetry group of the Toda is contained in that of the KdV equation. By an inverse process, discretization of the symmetry group of the KdV, we find a discrete clement of the symmetry group of the Toda lattice, which gives, by symmetry reduction, its soliton solution
Lie discrete symmetries of lattice equations
No full textWe extend two of the methods previously introduced to find discrete symmetries of differential equations to the case of difference and differential-difference equations. As an example of the application of the methods, we construct the discrete symmetries of the discrete Painleve I equation and of the Toda lattice equation
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Correspondence re: Aguilera NS, Tomaszewski MM, Moad JC, Bauer FA, Taubenberger JK, Abbondanzo SL. Cutaneous follicle center lymphoma: A clinicopatho logic study of 19 cases. Mod Pathol. 2001;14 : 828-35. and Franco R, Fernandez-Vazquez A, Mollejo M, Cruz MA, Camacho FI, Garcia JF, Navarrete M, Piris MA. Cutaneous presentation of follicular lymphomas. Mod Pathol. 2001;14 : 913-9. In reply
No full textON NONISOSPECTRAL FLOWS, PAINLEVE EQUATIONS, AND SYMMETRIES OF DIFFERENTIAL AND DIFFERENCE-EQUATIONS
No full textWe identify the Painleve Lax pairs with those corresponding to stationary solutions of non-isospectral flows, both for partial differential equations and differential-difference equations. We discuss symmetry reductions of integrable differential-difference equations and show that, in contrast with the continuous case, where Painleve' equations naturally arise, in the discrete case the so-called ''discrete Painleve equations'' cannot be obtained in this way. Actually, symmetry reductions of integrable differential-difference equations naturally provide ''delay Painleve equations. '
BRAF (V600E) Analysis by Immunohistochemistry in 204 Low-grade Glial and Glioneuronal Tumors
No full textAsymptotic symmetries and integrability: The KdV case
No full textIn this letter we consider asymptotic symmetries of the Korteweg de Vries equation, the prototype of the integrable equations. While the reduction of the KdV with respect to point and generalized symmetries gives equations of the Painleve classification, we show here that the reduction with respect to some asymptotic symmetries violates the Ablowitz-Ramani-Segur conjecture and gives an ordinary differential equation which does not possess the Painleve property. Copyright (c) EPLA, 2007
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