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This paper proves several generic variants of context lemmas and thus contributes to improving the tools to develop observational semantics that is based on a reduction semantics for a language. The context lemmas are provided for may- as well as two variants of mustconvergence and a wide class of extended lambda calculi, which satisfy certain abstract conditions. The calculi must have a form of node sharing, e.g. plain beta reduction is not permitted. There are two variants, weakly sharing calculi, where the beta-reduction is only permitted for arguments that are variables, and strongly sharing calculi, which roughly correspond to call-by-need calculi, where beta-reduction is completely replaced by a sharing variant. The calculi must obey three abstract assumptions, which are in general easily recognizable given the syntax and the reduction rules. The generic context lemmas have as instances several context lemmas already proved in the literature for specific lambda calculi with sharing. The scope of the generic context lemmas comprises not only call-by-need calculi, but also call-by-value calculi with a form of built-in sharing. Investigations in other, new variants of extended lambda-calculi with sharing, where the language or the reduction rules and/or strategy varies, will be simplified by our result, since specific context lemmas are immediately derivable from the generic context lemma, provided our abstract conditions are met.
We model sequential synchronous circuits on the logical level by signal-processing programs in an extended lambda calculus Lpor with letrec, constructors, case and parallel or (por) employing contextual equivalence. The model describes gates as (parallel) boolean operators, memory using a delay, which in turn is modeled as a shift of the list of signals, and permits also constructive cycles due to the parallel or. It opens the possibility of a large set of program transformations that correctly transform the expressions and thus the represented circuits and provides basic tools for equivalence testing and optimizing circuits. A further application is the correct manipulation by transformations of software components combined with circuits. The main part of our work are proof methods for correct transformations of expressions in the lambda calculus Lpor, and to propose the appropriate program transformations.
Call-by-need lambda calculi with letrec provide a rewritingbased operational semantics for (lazy) call-by-name functional languages. These calculi model the sharing behavior during evaluation more closely than let-based calculi that use a fixpoint combinator. In a previous paper we showed that the copy-transformation is correct for the small calculus LR-Lambda. In this paper we demonstrate that the proof method based on a calculus on infinite trees for showing correctness of instantiation operations can be extended to the calculus LRCC-Lambda with case and constructors, and show that copying at compile-time can be done without restrictions. We also show that the call-by-need and call-by-name strategies are equivalent w.r.t. contextual equivalence. A consequence is correctness of all the transformations like instantiation, inlining, specialization and common subexpression elimination in LRCC-Lambda. We are confident that the method scales up for proving correctness of copy-related transformations in non-deterministic lambda calculi if restricted to "deterministic" subterms.
The goal of this report is to prove correctness of a considerable subset of transformations w.r.t. contextual equivalence in a an extended lambda-calculus with case, constructors, seq, let, and choice, with a simple set of reduction rules. Unfortunately, a direct proof appears to be impossible. The correctness proof is by defining another calculus comprising the complex variants of copy, case-reduction and seq-reductions that use variablebinding chains. This complex calculus has well-behaved diagrams and allows a proof that of correctness of transformations, and also that the simple calculus defines an equivalent contextual order.
This paper extends the internal frank report 28 as follows: It is shown that for a call-by-need lambda calculus LRCCP-Lambda extending the calculus LRCC-Lambda by por, i.e in a lambda-calculus with letrec, case, constructors, seq and por, copying can be done without restrictions, and also that call-by-need and call-by-name strategies are equivalent w.r.t. contextual equivalence.
This paper proposes a possible way of assessing the effect of interest rate dynamics on changes in the decision-making approach, communication strategy and operational framework of a Central bank. Through a GARCH specification we show that the USA and Euro area displayed a limited but significant spillover of volatility from money market to longer-term rates. We then checked the stability of this phenomenon in the most recent period of improved policymaking and found empirical evidence that the transmission of overnight volatility along the yield curve vanished soon after specific policy changes of the FED and ECB.
Die vorliegende Arbeit ist eine kritische Auseinandersetzung mit dem Hofstedeschen Ansatz. Dabei soll in erster Linie das Werk von Hofstede selbst einer wissenschaftstheoretisch-methodologischen Prüfung unterzogen werden. Bei sehr populären Standardansätzen, die sowohl in der Praxis einen großen Anklang finden als auch in der wissenschaftlichen Gemeinschaft ständig rezipiert und weiterentwickelt werden, bleibt es natürlich nicht aus, dass durch Vereinfachungen oder Uminterpretationen in der Literatur Inkonsistenzen entstehen, die so im Originalwerk nicht enthalten sind. In dieser Arbeit soll es im Wesentlichen nicht um solche Probleme der Hofstedeschen Rezeption gehen. Vielmehr werde ich die Argumentation von Hofstede selbst in seinen eigenen Schriften […] einer detaillierten kritischen Analyse zu unterziehen, um auf diese Weise zu prüfen, ob bestimmte gravierende Probleme schon im Originalwerk angelegt sind.
Diese Studie analysiert die deutsche UN-Reformpolitik der letzten Jahre. Im Mittelpunkt steht eine kritische Auseinandersetzung mit der politischen Zielsetzung, einen nationalen ständigen Sitz für Deutschland im Sicherheitsrat der Vereinten Nationen zu erlangen. Vor dem Hintergrund prominenter Vorschläge zur Reform des Sicherheitsrats wird zunächst die Genese dieses Anspruchs rekonstruiert. In einem weiteren Schritt werden die Positionen wichtiger Verbündeter und Partner untersucht. Dabei wird deutlich, wie wenig Unterstützung Deutschland selbst von seinen wichtigsten Partnern erfährt und wie sehr diese Unterstützung in den letzten Jahren abgenommen hat. Die anschließende Analyse der wichtigsten Argumente für einen ständigen deutschen Sitz zeigt, dass sie einer kritischen Prüfung nicht Stand halten können. Die Studie schließt mit einem Plädoyer und konkreten Vorschlägen für eine Wiederbelebung einer europäischen Option.
Open-end real estate funds are of particular importance in the German bank-dominated financial system. However, recently the German open-end fund industry came under severe distress which triggered a broad discussion of required regulatory interventions. This paper gives a detailed description of the institutional structure of these funds and of the events that led to the crisis. Furthermore, it applies recent banking theory to openend real estate funds in order to understand why the open-end fund structure was so prevalent in Germany. Based on these theoretical insights we evaluate the various policy recommendations that have been raised.