The Experts below are selected from a list of 17937 Experts worldwide ranked by ideXlab platform
Mouhamed Moustapha Fall - One of the best experts on this subject based on the ideXlab platform.
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Nonexistence of distributional supersolutions of a semilinear elliptic equation with Hardy potential
Journal of Functional Analysis, 2013Co-Authors: Mouhamed Moustapha FallAbstract:Abstract In this paper we study Nonexistence of non-negative distributional supersolutions for a class of semilinear elliptic equations involving inverse-square potentials.
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Nonexistence results for a class of fractional elliptic boundary value problems
Journal of Functional Analysis, 2012Co-Authors: Mouhamed Moustapha Fall, Tobias WethAbstract:Abstract In this paper we study a class of fractional elliptic problems of the form { ( − Δ ) s u = f ( x , u ) in Ω , u = 0 in R N ∖ Ω , where s ∈ ( 0 , 1 ) . We prove Nonexistence of positive solutions when Ω is star-shaped and f is supercritical. We also derive a Nonexistence result for subcritical f in some unbounded domains. The argument relies on the method of moving spheres applied to a reformulated problem using the Caffarelli–Silvestre extension (Caffarelli and Silvestre (2007) [11] ) of a solution of the above problem.
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Nonexistence results for a class of fractional elliptic boundary value problems
arXiv: Analysis of PDEs, 2012Co-Authors: Mouhamed Moustapha Fall, Tobias WethAbstract:In this paper we study a class of fractional elliptic problems of the form $$ \Ds u= f(x,u) \quad \textrm{in} \O u=0\quad \textrm{in} \R^N \setminus \O,$$ where $s\in(0,1)$. We prove Nonexistence of positive solutions when $\O$ is star-shaped and $f$ is supercritical. We also derive a Nonexistence result for subcritical $f$ in some unbounded domains. The argument relies on the method of moving spheres applied to a reformulated problem using the Caffarelli-Silvestre extension \cite{CSilv} of a solution of the above problem. The standard approach in the case $s=1$ using Pohozaev type identities does not carry over to the case $0
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sharp Nonexistence results for a linear elliptic inequality involving hardy and leray potentials
Journal of Inequalities and Applications, 2011Co-Authors: Mouhamed Moustapha Fall, Roberta MusinaAbstract:We deal with nonnegative distributional supersolutions for a class of linear elliptic equations involving inverse-square potentials and logarithmic weights. We prove sharp Nonexistence results.
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sharp Nonexistence results for a linear elliptic inequality involving hardy and leray potentials
arXiv: Analysis of PDEs, 2010Co-Authors: Mouhamed Moustapha Fall, Roberta MusinaAbstract:In this paper we deal with nonnegative distributional supersolutions for a class of linear elliptic equations involving inverse-square potentials and logarithmic weights. We prove sharp Nonexistence results.
V Singh - One of the best experts on this subject based on the ideXlab platform.
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a new criterion for the overflow stability of second order state space digital filters using saturation arithmetic
IEEE Transactions on Circuits and Systems I-regular Papers, 1998Co-Authors: V SinghAbstract:Two recent approaches (one due to Singh [1990] and the other due to Liu and Michel [1992]) for the elimination of zero-input overflow oscillations in state-space digital filters designed with saturation arithmetic are compared. It is demonstrated that Singh's approach leads to a relatively less stringent condition for the Nonexistence of overflow oscillations. Using Singh's approach, an improved version of Ritzerfeld-Werter's criterion for the Nonexistence of overflow oscillations in second-order state-space digital filters is made available. Finally, a new zero-input limit cycle-free realizability condition for a generalized overflow characteristic is presented.
Phan Thanh Nam - One of the best experts on this subject based on the ideXlab platform.
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Nonexistence of large nuclei in the liquid drop model
Letters in Mathematical Physics, 2016Co-Authors: Rupert L Frank, Rowan Killip, Phan Thanh NamAbstract:We give a simplified proof of the Nonexistence of large nuclei in the liquid drop model and provide an explicit bound. Our bound is within a factor of 2.3 of the conjectured value and seems to be the first quantitative result.
Tobias Weth - One of the best experts on this subject based on the ideXlab platform.
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Nonexistence results for a class of fractional elliptic boundary value problems
Journal of Functional Analysis, 2012Co-Authors: Mouhamed Moustapha Fall, Tobias WethAbstract:Abstract In this paper we study a class of fractional elliptic problems of the form { ( − Δ ) s u = f ( x , u ) in Ω , u = 0 in R N ∖ Ω , where s ∈ ( 0 , 1 ) . We prove Nonexistence of positive solutions when Ω is star-shaped and f is supercritical. We also derive a Nonexistence result for subcritical f in some unbounded domains. The argument relies on the method of moving spheres applied to a reformulated problem using the Caffarelli–Silvestre extension (Caffarelli and Silvestre (2007) [11] ) of a solution of the above problem.
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Nonexistence results for a class of fractional elliptic boundary value problems
arXiv: Analysis of PDEs, 2012Co-Authors: Mouhamed Moustapha Fall, Tobias WethAbstract:In this paper we study a class of fractional elliptic problems of the form $$ \Ds u= f(x,u) \quad \textrm{in} \O u=0\quad \textrm{in} \R^N \setminus \O,$$ where $s\in(0,1)$. We prove Nonexistence of positive solutions when $\O$ is star-shaped and $f$ is supercritical. We also derive a Nonexistence result for subcritical $f$ in some unbounded domains. The argument relies on the method of moving spheres applied to a reformulated problem using the Caffarelli-Silvestre extension \cite{CSilv} of a solution of the above problem. The standard approach in the case $s=1$ using Pohozaev type identities does not carry over to the case $0
K. P. G. - One of the best experts on this subject based on the ideXlab platform.
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On the Nonexistence of degenerate phase-shift discrete solitons in a dNLS nonlocal lattice
'Elsevier BV', 2018Co-Authors: T. Penati, M. Sansottera, S. Paleari, K. P. G.Abstract:We consider a one-dimensional discrete nonlinear Schr\uf6dinger (dNLS) model featuring interactions beyond nearest neighbors. We are interested in the existence (or Nonexistence) of phase-shift discrete solitons, which correspond to four-sites vortex solutions in the standard two-dimensional dNLS model (square lattice), of which this is a simpler variant. Due to the specific choice of lengths of the inter-site interactions, the vortex configurations considered present a degeneracy which causes the standard continuation techniques to be non-applicable. In the present one-dimensional case, the existence of a conserved quantity for the soliton profile (the so-called density current), together with a perturbative construction, leads to the Nonexistence of any phase-shift discrete soliton which is at least C2 with respect to the small coupling \u3f5, in the limit of vanishing \u3f5. If we assume the solution to be only C0 in the same limit of \u3f5, Nonexistence is instead proved by studying the bifurcation equation of a Lyapunov-Schmidt reduction, expanded to suitably high orders. Specifically, we produce a Nonexistence criterion whose efficiency we reveal in the cases of partial and full degeneracy of approximate solutions obtained via a leading order expansion
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On the Nonexistence of degenerate phase-shift discrete solitons in a dNLS nonlocal lattice
'Elsevier BV', 2018Co-Authors: Penati T., Sansottera M., Paleari S., K. P. G.Abstract:We consider a one-dimensional discrete nonlinear Schr{\"o}dinger (dNLS) model featuring interactions beyond nearest neighbors. We are interested in the existence (or Nonexistence) of phase-shift discrete solitons, which correspond to four-sites vortex solutions in the standard two-dimensional dNLS model (square lattice), of which this is a simpler variant. Due to the specific choice of lengths of the inter-site interactions, the vortex configurations considered present a degeneracy which causes the standard continuation techniques to be non-applicable. In the present one-dimensional case, the existence of a conserved quantity for the soliton profile (the so-called density current), together with a perturbative construction, leads to the Nonexistence of any phase-shift discrete soliton which is at least $C^2$ with respect to the small coupling $\epsilon$, in the limit of vanishing $\epsilon$. If we assume the solution to be only $C^0$ in the same limit of $\epsilon$, Nonexistence is instead proved by studying the bifurcation equation of a Lyapunov-Schmidt reduction, expanded to suitably high orders. Specifically, we produce a Nonexistence criterion whose efficiency we reveal in the cases of partial and full degeneracy of approximate solutions obtained via a leading order expansion.Comment: 28 pages, slightly changed the title and other detail
