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On solvability of nonlinear operator equations and eigenvalues of homogeneous operators

Věra Burýšková, Slavomír Burýšek (1996)

Mathematica Bohemica

Notions as the numerical range W ( S , T ) and the spectrum ( S , T ) of couple ( S , T ) of homogeneous operators on a Banach space are used to derive theorems on solvability of the equation S x - l T x = y . Conditions for the existence of eigenvalues of the couple ( S , T ) are given.

On the blow-up phenomenon for the mass-critical focusing Hartree equation in ℝ⁴

Changxing Miao, Guixiang Xu, Lifeng Zhao (2010)

Colloquium Mathematicae

We characterize the dynamics of the finite time blow-up solutions with minimal mass for the focusing mass-critical Hartree equation with H¹(ℝ⁴) data and L²(ℝ⁴) data, where we make use of the refined Gagliardo-Nirenberg inequality of convolution type and the profile decomposition. Moreover, we analyze the mass concentration phenomenon of such blow-up solutions.

On the Conley index in Hilbert spaces in the absence of uniqueness

Marek Izydorek, Krzysztof P. Rybakowski (2002)

Fundamenta Mathematicae

Consider the ordinary differential equation (1) ẋ = Lx + K(x) on an infinite-dimensional Hilbert space E, where L is a bounded linear operator on E which is assumed to be strongly indefinite and K: E → E is a completely continuous but not necessarily locally Lipschitzian map. Given any isolating neighborhood N relative to equation (1) we define a Conley-type index of N. This index is based on Galerkin approximation of equation (1) by finite-dimensional ODEs and extends...

On the convergence and application of Stirling's method

Ioannis K. Argyros (2003)

Applicationes Mathematicae

We provide new sufficient convergence conditions for the local and semilocal convergence of Stirling's method to a locally unique solution of a nonlinear operator equation in a Banach space setting. In contrast to earlier results we do not make use of the basic restrictive assumption in [8] that the norm of the Fréchet derivative of the operator involved is strictly bounded above by 1. The study concludes with a numerical example where our results compare favorably with earlier ones.

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