Results 31 to 40 of about 160 (145)

Linearization of hyperbolic resonant fixed points of diffeomorphisms with related Gevrey estimates in the planar case

Electronic Journal of Differential Equations, 2017
We show that any germ of smooth hyperbolic diffeomophism at a fixed point is conjugate to its linear part, using a transformation with a Mourtada type functions, which (roughly) means that it may contain terms like $x \log |x|$.
Patrick Bonckaert, Vincent Naudot
doaj  

New Lower Bounds of Spatial Analyticity Radius for the Kawahara Equation

International Journal of Differential Equations, Volume 2025, Issue 1, 2025.
In this paper, an algebraic decay rate for the radius of spatial analyticity of solutions to the Kawahara equation ∂tu+β∂x5u+α∂x3u+u∂xu=00,β≠ is investigated. With given analytic initial data having a fixed radius of analyticity σ0, we derive an algebraic decay rate σ(t) ~ |t|−1/2 for the uniform radius of spatial analyticity of solutions to the ...
Tegegne Getachew, Jaume Giné
wiley   +1 more source

The Zahorski theorem is valid in Gevrey classes [PDF]

Fundamenta Mathematicae, 1996
The well-known Zahorski theorem [\textit{Z. Zahorski}, Fundam. Math. 34, 183-245 (1947; Zbl 0033.25504)] asserts that for every partition \(\{\Omega,F,G\}\) of \([0,1]\subset\mathbb{R}\), where \(\Omega\) is an open subset of \([0,1]\), \(F\) is a (Baire) first category \(F_\sigma\)-subset of \([0,1]\) and \(G\) is a \(G_\delta\)-subset of \([0,1 ...
Schmets, Jean, Valdivia, Manuel
openaire   +2 more sources

Asymptotic Lower Bound on the Spatial Analyticity Radius for Solutions of the Periodic Fifth Order KdV–BBM Equation

International Journal of Differential Equations, Volume 2025, Issue 1, 2025.
In this work, consideration is given to the initial value problem associated with the periodic fifth‐order KdV–BBM equation. It is shown that the uniform radius of spatial analyticity σ(t) of solution at time t is bounded from below by ct−2/3 (for some c > 0), given initial data η0 that is analytic on the circle and has a uniform radius of spatial ...
Tegegne Getachew, Giovanni P. Galdi
wiley   +1 more source

Taming non-analyticities of QFT observables

Journal of High Energy Physics
Many observables in quantum field theories are involved non-analytic functions of the parameters of the theory. However, it is expected that they are not arbitrarily wild, but rather have only a finite amount of geometric complexity. This expectation has
Thomas W. Grimm, Giovanni Ravazzini, Mick van Vliet   +2 more
doaj   +1 more source

Algebraic Lower Bounds on the Spatial Analyticity Radius for Higher Order Nonlinear Schrödinger Equations

Journal of Applied Mathematics, Volume 2025, Issue 1, 2025.
We investigate the initial value problem associated to the higher order nonlinear Schrödinger equation i∂tu+−1j+1∂x2ju=u2ju x,t≠0∈ℝ,ux,0=u0x, where j ≥ 2 is any integer, u is a complex valued function, and the initial data u0 is real analytic on ℝ and has a uniform radius of spatial analyticity σ0 in the space variable.
Tegegne Getachew, Birilew Belayneh, Betre Shiferaw, Huaiqin Wu   +3 more
wiley   +1 more source

Decay Rate on the Radius of Spatial Analyticity to Solutions for the Modified Camassa–Holm Equation

Journal of Mathematics, Volume 2025, Issue 1, 2025.
The initial value problem associated with the modified Camassa–Holm equation for initial data u0(x) that is analytic on the line and having uniform radius of spatial analyticity σ0 is considered. We have shown the persistence of the radius of spatial analyticity till some time δ.
Tegegne Getachew, Yongqiang Fu
wiley   +1 more source

Cauchy problem for hyperbolic systems in Gevrey class. A note on Gevrey indices [PDF]

Annales de la Faculté des sciences de Toulouse : Mathématiques, 2000
The author considers the hyperbolic system \[ \begin{gathered} [I_4 D_t+ A(t) D_x+ B(t)]u(t,x)= 0,\\ u(0,x)= u_0(x)\end{gathered} \] in \(\Omega= [0,T]\times \mathbb{R}^1_x\) where \(I_4\) denotes the unit matrix of order 4 and \[ A(t)= \begin{pmatrix} \lambda(t) & 1 & 0 & 0\\ 0 &\lambda(t) & a(t) & 0\\ 0 & 0 & \mu(t) & 1\\ 0 & 0 & 0 & \mu(t)\end ...
openaire   +2 more sources

de Sitter State in Heterotic String Theory

Fortschritte der Physik, Volume 72, Issue 11, November 2024.
Abstract Recent no‐go theorems have ruled out four‐dimensional classical de Sitter vacua in heterotic string theory. On the other hand, the absence of a well‐defined Wilsonian effective action and other related phenomena also appear to rule out such time‐dependent vacua with de Sitter isometries, even in the presence of quantum corrections.
Stephon Alexander, Keshav Dasgupta, Archana Maji, Pichai Ramadevi, Radu Tatar   +4 more
wiley   +1 more source