On the relative strengths of fragments of collection

Let $\mathbf{M}$ be the basic set theory that consists of the axioms of extensionality, emptyset, pair, union, powerset, infinity, transitive containment, $\Delta_0$-separation and set foundation. This paper studies the relative strength of set theories obtained by adding fragments of the set-theoretic collection scheme to $\mathbf{M}$. We focus on two common parameterisations of collection: $\Pi_n$-collection, which is the usual collection scheme restricted to $\Pi_n$-formulae, and strong $\Pi_n$-collection, which is equivalent to $\Pi_n$-collection plus $\Sigma_{n+1}$-separation. The main result of this paper shows that for all $n \geq 1$, (1) $\mathbf{M}+\Pi_{n+1}\textrm{-collection}+\Sigma_{n+2}\textrm{-induction on } \omega$ proves the consistency of Zermelo Set Theory plus $\Pi_{n}$-collection, (2) the theory $\mathbf{M}+\Pi_{n+1}\textrm{-collection}$ is $\Pi_{n+3}$-conservative over the theory $\mathbf{M}+\textrm{strong }\Pi_n \textrm{-collection}$. It is also shown that (2) holds for $n=0$ when the Axiom of Choice is included in the base theory. The final section indicates how the proofs of (1) and (2) can be modified to obtain analogues of these results for theories obtained by adding fragments of collection to a base theory (Kripke-Platek Set Theory with Infinity and $V=L$) that does not include the powerset axiom.Comment: 22 page

Regulating Television and the Case of Football World Cup

This paper deals with EU-Directive 89/552/EEC "Television Without Frontiers", which enables each EU-country to set up a list of major events that are not allowed to be transmitted in Pay-TV. We analyze this kind of regulation using instruments of game-theory and monopoly-theory. We compare the market results of the EU-Regulation with two alternative arrangements, namely with a general ban of Pay-TV and with a 'laisser-faire'-solution. Our model shows that a selective ban may be welfare-superior to both other forms of Pay-TV treatment. Finally we show that there are good arguments to forbid Pay-TV-broadcasting of major football events. -- Dieses Paper beschäftigt sich mit der Frage, ob sportliche Großereignisse im Pay-TV oder im Free-TV übertragen werden sollten. Aktueller Anlaß für eine breite Diskussion dieses Themas ist der Kauf der Übertragungsrechte für die Fußballweltmeisterschaften 2002 und 2006 durch die ISL/Kirch-Gruppe. Verfechter einer weit-reichenden Regulierung des Fernsehmarktes befürworten Maßnahmen, die bis zu einem Verbot von Pay-TV reichen. Andere wollen hingegen der ISL/Kirch-Gruppe die freie Vermarktung ihrer Rechte belassen. Unsere Analyse nähert sich dem Problem aus ökonomischer Sicht. Wir gehen dabei von einem dreistufigen Fernsehmarkt aus, in dem ein Erstrechteinhaber als Monopolanbieter die Übertragungslizenz vergibt. Auf einer zweiten Stufe entscheidet der Lizenznehmer über die Ausstrahlungsform. Die unterste Ebene ist von fußballbegeisterten Fernsehzuschauern geprägt, die eine wertvolle Zielgruppe für die Werbewirtschaft darstellen. In einem einfachen monopoltheoretischen Modell werden Bedingungen abgeleitet, unter denen eine Regulie-rung des Fernsehmarktes erfolgen sollte. Unsere Empfehlungen stützen sich dabei auf eine wohlfahrtsökonomische Bewertung der Modellergebnisse.Pay-TV,Football,Media economics,Advertising,Applied Game Theory,EU-Directive 89/552/EEC

Lockdown: Dynamic Control-Flow Integrity

Applications written in low-level languages without type or memory safety are especially prone to memory corruption. Attackers gain code execution capabilities through such applications despite all currently deployed defenses by exploiting memory corruption vulnerabilities. Control-Flow Integrity (CFI) is a promising defense mechanism that restricts open control-flow transfers to a static set of well-known locations. We present Lockdown, an approach to dynamic CFI that protects legacy, binary-only executables and libraries. Lockdown adaptively learns the control-flow graph of a running process using information from a trusted dynamic loader. The sandbox component of Lockdown restricts interactions between different shared objects to imported and exported functions by enforcing fine-grained CFI checks. Our prototype implementation shows that dynamic CFI results in low performance overhead.Comment: ETH Technical Repor

Gauge-Independent Scales Related to the Standard Model Vacuum Instability

The measured (central) values of the Higgs and top quark masses indicate that the Standard Model (SM) effective potential develops an instability at high field values. The scale of this instability, determined as the Higgs field value at which the potential drops below the electroweak minimum, is about $10^{11}$ GeV. However, such a scale is unphysical as it is not gauge-invariant and suffers from a gauge-fixing uncertainty of up to two orders of magnitude. Subjecting our system, the SM, to several probes of the instability (adding higher order operators to the potential; letting the vacuum decay through critical bubbles; heating up the system to very high temperature; inflating it) and asking in each case physical questions, we are able to provide several gauge-invariant scales related with the Higgs potential instability.Comment: 44 pages, 9 figure

Definable orthogonality classes in accessible categories are small

We lower substantially the strength of the assumptions needed for the validity of certain results in category theory and homotopy theory which were known to follow from Vopenka's principle. We prove that the necessary large-cardinal hypotheses depend on the complexity of the formulas defining the given classes, in the sense of the Levy hierarchy. For example, the statement that, for a class S of morphisms in a locally presentable category C of structures, the orthogonal class of objects is a small-orthogonality class (hence reflective) is provable in ZFC if S is \Sigma_1, while it follows from the existence of a proper class of supercompact cardinals if S is \Sigma_2, and from the existence of a proper class of what we call C(n)-extendible cardinals if S is \Sigma_{n+2} for n bigger than or equal to 1. These cardinals form a new hierarchy, and we show that Vopenka's principle is equivalent to the existence of C(n)-extendible cardinals for all n. As a consequence, we prove that the existence of cohomological localizations of simplicial sets, a long-standing open problem in algebraic topology, is implied by the existence of arbitrarily large supercompact cardinals. This result follows from the fact that cohomology equivalences are \Sigma_2. In contrast with this fact, homology equivalences are \Sigma_1, from which it follows (as is well known) that the existence of homological localizations is provable in ZFC.Comment: 38 pages; some results have been improved and former inaccuracies have been correcte

Fourier's Law from Schroedinger Dynamics

We consider a class of one-dimensional chains of weakly coupled many level systems. We present a theory which predicts energy diffusion within these chains for almost all initial states, if some concrete conditions on their Hamiltonians are met. By numerically solving the time dependent Schroedinger equation, we verify this prediction. Close to equilibrium we analyze this behavior in terms of heat conduction and compute the respective coefficient directly from the theory.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

Vital Sign Ontology

We introduce the Vital Sign Ontology (VSO), an extension of the Ontology for General Medical Science (OGMS) that covers the consensus human vital signs: blood pressure, body temperature, respiratory rate, and pulse rate. VSO provides a controlled structured vocabulary for describing vital sign measurement data, the processes of measuring vital signs, and the anatomical entities participating in such measurements. VSO is implemented in OWL-DL and follows OBO Foundry guidelines and best practices. If properly developed and extended, we believe the VSO will find applications for the EMR, clinical informatics, and medical device communities

Solving the BM Camelopardalis puzzle

BM Camelopardalis (=12 Cam) is a chromospherically active binary star with a relatively large orbital eccentricity. Systems with large eccentricities usually rotate pseudosynchronously. However, BM Cam has been a puzzle since its observed rotation rate is virtually equal to its orbital period indicating synchronization. All available photometry data for BM Cam have been collected and analyzed. Two models of modulated ellipticity effect are proposed, one based on equilibrium tidal deformation of the primary star and the other on a dynamical tidal effect. When the starspot variability is removed from the data, the dynamical tidal model was the better approximation to the real physical situation. The analysis indicates that BM Cam is not rotating pseudosynchronously but rotating in virtual synchronism after all

In vivo imaging of the tonoplast intrinsic protein family in Arabidopsis roots

Background: Tonoplast intrinsic proteins (TIPs) are widely used as markers for vacuolar compartments in higher plants. Ten TIP isoforms are encoded by the Arabidopsis genome. For several isoforms, the tissue and cell specific pattern of expression are not known. Results: We generated fluorescent protein fusions to the genomic sequences of all members of the Arabidopsis TIP family whose expression is predicted to occur in root tissues (TIP1;1 and 1;2; TIP2;1, 2;2 and 2;3; TIP4;1) and expressed these fusions, both individually and in selected pairwise combinations, in transgenic Arabidopsis. Analysis by confocal microscopy revealed that TIP distribution varied between different cell layers within the root axis, with extensive co-expression of some TIPs and more restricted expression patterns for other isoforms. TIP isoforms whose expression overlapped appeared to localise to the tonoplast of the central vacuole, vacuolar bulbs and smaller, uncharacterised structures. Conclusion: We have produced a comprehensive atlas of TIP expression in Arabidopsis roots, which reveals novel expression patterns for not previously studied TIPs