A Comprehensive Framework for Controlled Query Evaluation, Consistent Query Answering and KB Updates in Description Logics

In this extended abstract we discuss the relationship between confidentiality-preserving frameworks and inconsistency-tolerant repair and update semantics in Description Logics (DL). In particular, we consider the well-known problems of Consistent Query Answering, Controlled Query Evaluation, and Knowledge Base Update in DL and introduce a unifying framework that can be naturally instantiated to capture significant settings for the above problems, previously investigated in the literature

What is (not) wrong with scalar gravity?

On his way to General Relativity (GR) Einstein gave several arguments as to why a special relativistic theory of gravity based on a massless scalar field could be ruled out merely on grounds of theoretical considerations. We re-investigate his two main arguments, which relate to energy conservation and some form of the principle of the universality of free fall. We find that such a theory-based a priori abandonment not to be justified. Rather, the theory seems formally perfectly viable, though in clear contradiction with (later) experiments. This may be of interest to those who teach GR and/or have an active interest in its history.Comment: 26 pages, 3 figure

On the possibility of spinorial quantization in the Skyrme model

We consider the configuration space of the Skyrme model and give a simple proof that loops generated by full spatial rotations are contractible in the even-, and non-contractible in the odd-winding-number sectors.Comment: Plain-Tex, 9 pages, no figures, Freiburg THEP-92/3

Gallstones: Bad Company for the Steatotic Liver

Gallstones are very frequent worldwide with a prevalence ranging from 10% to 15% in Western countries to <5% in Africa, with the geographic variations being associated with genetic and environmental factors.1 Although asymptomatic in more than 80% of patients, gallstone disease incurs one of the highest health care costs among digestive diseases and hospitalization is frequent as a consequence of its complications

Is There a General Area Theorem for Black Holes?

The general validity of the area law for black holes is still an open problem. We first show in detail how to complete the usually incompletely stated text-book proofs under the assumption of piecewise $C^2$-smoothness for the surface of the black hole. Then we prove that a black hole surface necessarily contains points where it is not $C^1$ (called ``cusps'') at any time before caustics of the horizon generators show up, like e.g. in merging processes. This implies that caustics never disappear in the past and that black holes without initial cusps will never develop such. Hence black holes which will undergo any non-trivial processes anywhere in the future will always show cusps. Although this does not yet imply a strict incompatibility with piecewise $C^2$ structures, it indicates that the latter are likely to be physically unnatural. We conclude by calling for a purely measure-theoretic proof of the area theorem.Comment: 7 pages, TeX; the proof for existence of cusps is generalized, new material and references include

Complex multiplication and Brauer groups of K3 surfaces

Inspired by the classical theory of CM abelian varieties, in this paper we discuss the theory of complex multiplication for K3 surfaces. Let $X$ be a complex K3 surface with complex multiplication by the maximal order $\mathcal{O}_E$ of a CM field $E$. We compute the field of moduli of triples $(T(X), B, \iota)$, where $T(X)$ denotes the transcendental lattice of $X$, $B \subset \text{Br}(X)$ a finite, $\mathcal{O}_E$-invariant subgroup and $\iota \colon E \rightarrow \text{End}_{\text{Hdg}}(T(X)_{\mathbb{Q}})$ an isomorphism. If $X$ is defined over a number field $K$, we show how our results can be efficiently implemented to study the Galois-invariant part of the geometric Brauer group of $X$. As an application, we list all the possible groups that can appear as $\text{Br}(X)^{\Gamma_K}$ when $X$ has (geometric) maximal Picard rank, $K$ is the field of moduli of $(T(X)_{\mathbb{C}}, \iota)$ and $\Gamma_K$ denotes its absolute Galois group

Charged-particle multiplicity with ALICE at the LHC

The pseudorapidity density and multiplicity distributions of charged particles have been the first measurements carried out with the ALICE detector at the LHC. After an introduction on the experiment and some details on the subdetectors relevant for these measurements, results from minimum bias proton-proton collisions at 0.9, 2.36 and 7 TeV are presented. Comparisons with other measurements and model predictions are also discussed.Comment: 6 pages, 4 figures, 2 tables; Il Nuovo Cimento (2011