The algorithmic facet of euclidean lattices is a frequent tool in computer science and mathematics. It mainly relies on the LLL reduction, making worthwile efficiency improvements. Schnorr proved that the LLL algorithm can be speeded up if one computes approximations to the underlying Gram-Schmidt orthogonalisations. Without approximations, these computations dominate the cost of the reduction....

The goal of this paper is to establish the applicability of the Lyapunov-Schmidt reduction and the Centre Manifold Theorem for a class of hyperbolic partial differential equation models with nonlocal interaction terms describing the aggregation dynamics of animals/cells in a one-dimensional domain with periodic boundary conditions. We show the Fredholm property for the linear operator obtained ...

The idea behind the SizeReduce(B) subroutine is, in the Gram-Schmidt decomposition B = B̃ ·U, to shift the entries in the upper triangle of U by integers (via unimodular transformations), so that they lie in [−12 , 1 2). Because changing an entry of U may affect the ones above it (but not below it) in the same column, we must make the changes upward in each column. Formally, the algorithm works ...

An infectious disease model with latent infection is studied, and the basic reproductio n number of obtained When reproducing less than 1, mode l has only one disease-free equilibrium. greater t he equilibrium unstable. The also a unique positive global asymptotic stability two equilibria analyzed by linearization method, Liapunov function method geometric method.

(K1) K ∈ C(R), K is bounded and K(x) > 0 ∀ x ∈ R. One seeks solutions uε of (NLS) that concentrate, as ε→ 0, near some point x0 ∈ R (semiclassical standing waves). By this we mean that for all x ∈ R \ {x0} one has that uε(x) → 0 as ε→ 0. When K equals a positive constant, say K(x) ≡ 1, (NLS) has been widely investigated, see [2, 3, 10, 12, 15, 16, 18] and references therein. Moreover, the exist...

Within the Liapunov framework, a sufficient condition for uniform asymptotic stability of ordinary differential equations is proposed. Unlike with classical Liapunov theory, the time derivative of the V -function, taken along solutions of the system, may have positive and negative values. It is shown that the proposed condition is useful for the study of uniform asymptotic stability of homogene...

In these notes we discuss Markov processes, in particular stochastic differential equations (SDE) and develop some tools to analyze their long-time behavior. There are several ways to analyze such properties, and our point of view will be to use systematically Liapunov functions which allow a nice characterization of the ergodic properties. In this we follow, at least in spirit, the excellent b...