La plate-forme "Corpus de langues parlées en interaction" (CLAPI) : historique, états des lieux, perspectives

http://lidil.revues.org/index139.htm

Superpolynomial smoothed complexity of 3-FLIP in Local Max-Cut

We construct a graph with $n$ vertices where the smoothed runtime of the 3-FLIP algorithm for the 3-Opt Local Max-Cut problem can be as large as $2^{\Omega(\sqrt{n})}$. This provides the first example where a local search algorithm for the Max-Cut problem can fail to be efficient in the framework of smoothed analysis. We also give a new construction of graphs where the runtime of the FLIP algorithm for the Local Max-Cut problem is $2^{\Omega(n)}$ for any pivot rule. This graph is much smaller and has a simpler structure than previous constructions.Comment: 18 pages, 3 figure

Determining Inversion Barriers in Atrop- isomers - A Tutorial for Organic Chemists

Dynamic behavior is a fascinating property of natural and artificial systems and its understanding has significantly impacted the transformation of molecular interchanges into controlled molecular motion. In this tutorial, the key descriptors of enantiomeric stability are examined in-depth. Enantiomerization and racemization are discussed and differentiated on a fundamental level proposing a unified and distinct nomenclature. Their mathematical meanings and relations are described and deduced cohesively in the context of atropisomerization. The calculation of inversion barriers from thermodynamic and kinetic data is demonstrated and the interdependences between the latter are explained mathematically. Using current examples from our group, the determination of rate constants and the thermodynamic parameters is shown in a step-by-step manner using the most common techniques. The tutorial is concluded with aspects and considerations concerning statistical data analysis and error determination of measurements including a practical guide to Monte-Carlo simulations

The structure and density of kk-product-free sets in the free semigroup

The free semigroup $\mathcal{F}$ over a finite alphabet $\mathcal{A}$ is the set of all finite words with letters from $\mathcal{A}$ equipped with the operation of concatenation. A subset $S$ of $\mathcal{F}$ is $k$-product-free if no element of $S$ can be obtained by concatenating $k$ words from $S$, and strongly $k$-product-free if no element of $S$ is a (non-trivial) concatenation of at most $k$ words from $S$. We prove that a $k$-product-free subset of $\mathcal{F}$ has upper Banach density at most $1/\rho(k)$, where $\rho(k) = \min\{\ell \colon \ell \nmid k - 1\}$. We also determine the structure of the extremal $k$-product-free subsets for all $k \notin \{3, 5, 7, 13\}$; a special case of this proves a conjecture of Leader, Letzter, Narayanan, and Walters. We further determine the structure of all strongly $k$-product-free sets with maximum density. Finally, we prove that $k$-product-free subsets of the free group have upper Banach density at most $1/\rho(k)$, which confirms a conjecture of Ortega, Ru\'{e}, and Serra.Comment: 31 pages, added density results for the free grou

Towards a Trust Concept for Web Based Services of Heating, Ventilation and Air Conditioning Systems in the Smart Home

Usage of smart home solutions implies generation, processing, and storage of machine and personal data. Recently made public cases of data breaches and misuse increased peoples’ concerns of data security and decreased the trust in secure data handling and smart home technologies. Hence potential benefits are not exploited. It is therefore necessary to analyse how manufacturers can increase their online trust perception. Requirements of (potential) customers of web based services for HVAC systems are identified using thematic analysis for 23 conducted interviews using online trust perception literature as basis. Manufacturer independent websites are derived as the most important online touch point for customers with manufacturers and products. Determined content and structure measures for online touch points managed by manufacturers derived to positively influence the manufacturer and manufacturer independent touch points regarding perception of trust. The derived trust concept must be evaluated in the following using the defined evaluation plan

Universe's Primordial Quantum Memories

We provide a very general argument showing that the Universe must have kept its quantum memories from an epoch much earlier than $60$ e-foldings before the end of inflation. The point is that a generic system of enhanced memory storage capacity exhibits a phenomenon of memory burden. Due to its universal nature this effect must be applicable to de Sitter since the latter has a maximal memory storage capacity thanks to its Gibbons-Hawking entropy. The primordial information pattern encoded in de Sitter memory initially costs very little energy. However, because of Gibbons-Hawking evaporation, the memory burden of the pattern grows in time and increasingly back reacts on the evaporation process. After a finite time the memory burden becomes unbearable and de Sitter quantum breaks. If inflation ended not long before its quantum break-time, the imprints of the primordial memory pattern can be observable. This provides a qualitatively new type of window in the Universe's beginning, a sort of cosmic quantum hair.Comment: 9 pages, 2 figure

Black Hole Metamorphosis and Stabilization by Memory Burden

Systems of enhanced memory capacity are subjected to a universal effect of memory burden, which suppresses their decay. In this paper, we study a prototype model to show that memory burden can be overcome by rewriting stored quantum information from one set of degrees of freedom to another one. However, due to a suppressed rate of rewriting, the evolution becomes extremely slow compared to the initial stage. Applied to black holes, this predicts a metamorphosis, including a drastic deviation from Hawking evaporation, at the latest after losing half of the mass. This raises a tantalizing question about the fate of a black hole. As two likely options, it can either become extremely long lived or decay via a new classical instability into gravitational lumps. The first option would open up a new window for small primordial black holes as viable dark matter candidates.Comment: 34 pages, 8 figures, 1 appendi

Abundance: Asymmetric Graph Removal Lemmas and Integer Solutions to Linear Equations

We prove that a large family of pairs of graphs satisfy a polynomial dependence in asymmetric graph removal lemmas. In particular, we give an unexpected answer to a question of Gishboliner, Shapira, and Wigderson by showing that for every $t \geqslant 4$, there are $K_t$-abundant graphs of chromatic number $t$. Using similar methods, we also extend work of Ruzsa by proving that a set $\mathcal{A} \subset \{1,\dots,N\}$ which avoids solutions with distinct integers to an equation of genus at least two has size $\mathcal{O}(\sqrt{N})$. The best previous bound was $N^{1 - o(1)}$ and the exponent of $1/2$ is best possible in such a result. Finally, we investigate the relationship between polynomial dependencies in asymmetric removal lemmas and the problem of avoiding integer solutions to equations. The results suggest a potentially deep correspondence. Many open questions remain.Comment: 28 pages, 4 figure