Glauber dynamics for the mean-field Ising model: cut-off, critical power law, and metastability

We study the Glauber dynamics for the Ising model on the complete graph, also known as the Curie–Weiss Model. For β < 1, we prove that the dynamics exhibits a cut-off: the distance to stationarity drops from near 1 to near 0 in a window of order n centered at [2(1 ? β)]^?1 n log n. For β = 1, we prove that the mixing time is of order n ^3/2. For β > 1, we study metastability. In particular, we show that the Glauber dynamics restricted to states of non-negative magnetization has mixing time O(n log n).     

A complete estimate on the localization for a porous medium type equation

This paper is concerned with the porous medium equation $$u_{t}={\rm div}(u^{\sigma} \nabla u) +u^{\beta},\,\,(x, t) \in R^{N} \times (0,T),$$ where σ >  0, β >  σ +  1, and the blowing-up time T <  ∞. It is shown in [5,7] that the solution u(x,t) is localized in the case when the initial function has a compact support. In addition, an estimate on the size of the localization in terms of the initial support and the blowing-up time T is partially derived in [5] if β >  σ +  3. In this paper we give a complete estimate on the localization for all β >  σ +  1.     

Boundary proximity of SLE

This paper examines how close the chordal SLE _κ curve gets to the real line asymptotically far away from its starting point. In particular, when κ ? (0, 4), it is shown that if β > β _κ  := 1/(8/κ ? 2), then the intersection of the SLE _κ curve with the graph of the function y = x/(log x) ^β , x > e, is a.s. bounded, while it is a.s. unbounded if β = β _κ . The critical SLE₄ curve a.s. intersects the graph of $y=x^{{-({\rm log\,log\,x})}^{\alpha}}, x > e^e$ , x > e ^e , in an unbounded set if α ≤ 1, but not if α > 1. Under a very mild regularity assumption on the function y(x), we give a necessary and sufficient integrability condition for the intersection of the SLE _κ path with the graph of y to be unbounded. When the intersection is bounded a.s., we provide an estimate for the probability that the SLE _κ path hits the graph of y. We also prove that the Hausdorff dimension of the intersection set of the SLE _κ curve and the real axis is 2 ? 8/κ when 4 < κ < 8.     

On the Gibbs properties of the Erdös measure

We consider the infinite convolved Bernoulli measures (Bernoulli convolutions) related to β-numeration. A Markovian matrix decomposition of these measures is obtained when β is a Pisot number whose associated β-shift is of finite type. We study the special case of the Erdös measure (i.e., when β is the golden ratio) that we prove to be weak Gibbs, insuring the multifractal formalism to hold. To cite this article: E. Olivier, C. R. Acad. Sci. Paris, Ser. I 336 (2003).     

Hyers–Ulam Stability of General Jensen-Type Mappings in Banach Algebras

Using the fixed point method, we prove the Hyers–Ulam stability of homomorphisms in complex Banach algebras and complex Banach Lie algebras and also of derivations on complex Banach algebras and complex Banach Lie algebras for the general Jensen-type functional equation f(α x + β y) + f(α x ? β y) = 2α f(x) for any \({\alpha, \beta \in \mathbb{R}}\) with \({\alpha, \beta \neq 0}\) . Furthermore, we prove the hyperstability of homomorphisms in complex Banach algebras for the above functional equation with α = β = 1.     

Generalized skew derivations with nilpotent values on Lie ideals

Let R be a prime ring and L a noncommutative Lie ideal of R. Suppose that f is a right generalized β-derivation of R associated with a β-derivation δ such that f(x) ⁿ  = 0 for all ${x\in L}$ , where n is a fixed positive integer. Then f = 0.     

The size of irregular points for a measure

For a measure μ on the complex plane μ-regular points play an important role in various polynomial inequalities. In the present work it is shown that every point in the set {μ′>0} (actually of a larger set where μ is strong) with the exception of a set of zero logarithmic capacity is a μ-regular point. Here “set of zero logarithmic capacity” cannot be replaced by “β-logarithmic Hausdorff measure  0” with β=1 (it can be replaced by “β-logarithmic measure 0” with any β>1). On the other hand, for arbitrary μ the set of μ-regular points can be quite small, but never empty.     

Proof of the bandwidth conjecture of Bollobás and Komlós

In this paper we prove the following conjecture by Bollobás and Komlós: For every γ > 0 and integers r ≥ 1 and Δ, there exists β > 0 with the following property. If G is a sufficiently large graph with n vertices and minimum degree at least ((r ? 1)/r + γ)n and H is an r-chromatic graph with n vertices, bandwidth at most β n and maximum degree at most Δ, then G contains a copy of H.