The pp-adic Shintani cocycle

The Shintani cocycle on \GL_n(\Q), as constructed by Hill, gives a cohomological interpretation of special values of zeta functions for totally real fields of degree $n$. We give an explicit criterion for a specialization of the Shintani cocycle to be $p$-adically interpolable. As a corollary, we recover the results of Deligne-Ribet, Cassou Nogu\`es and Barsky on the construction of $p$-adic $L$-functions attached to totally real fields.Comment: 19 pages. v2: Corrected several typo

Orientifolds of Warped Throats from Toric Calabi-Yau Singularities

We study the complex deformations of orientifolds of D3-branes at toric CY singularities, using their description in terms of dimer diagrams. We describe orientifold quotients that have fixed lines or fixed points in the dimer, and characterize the possibilities to deform them in terms of the behaviour of zig-zag paths under the orientifold symmetry. The resulting models are holographic duals to warped throats with orientifold planes. Our systematic construction provides a general class of configurations which includes models recently appeared in the context of de Sitter uplift by nilpotent goldstino or dynamical supersymmetry breaking.Comment: 39 pages, 23 figures. v2: minor corrections don

Pricing of Warrants with Stock Price Dependent Threshold Conditions

Warrants with stock price dependent threshold conditions give the right to buy specially issued stocks, if the performance of the stock price satisfies some requirements. Existence of these derivatives changes the price process of the underlying. We show that in the presence of such warrants one cannot assume that the stock market is arbitrage free and that the stock is tradeable at every time moment with the same price for buying and selling. This means that the usual methods for deriving fair prices for such warrants cannot be used. We start from a simple model for the firm's value process and discuss some ways to specify a related model for the stock price process in the presence of warrants with threshold conditions. We also discuss how indifference pricing approach can be used for pricing such warrants

De Sitter Uplift with Dynamical Susy Breaking

We propose the use of D-brane realizations of Dynamical Supersymmetry Breaking (DSB) gauge sectors as sources of uplift in compactifications with moduli stabilization onto de Sitter vacua. This construction is fairly different from the introduction of anti D-branes, yet allows for tunably small contributions to the vacuum energy via their embedding into warped throats. The idea is explicitly exemplified by the embedding of the 1-family $SU(5)$ DSB model in a local warped throat with fluxes, which we discuss in detail in terms of orientifolds of dimer diagrams.Comment: 26 pages, 16 figures. v3: version accepted in JHEP with minor corrections in the introduction and extra reference

Credit constraints, firms' precautionary investment and the business cycle

This paper studies the macroeconomic implications of firms' investment composition choices in the presence of credit constraints. Following a negative and persistent aggregate productivity shock, firms shift into short-term investments because they produce more pledgeable output and because they help alleviate future borrowing constraints. This produces a short-run dampening of the effects of the shock, at the expense of lower long-term investment and future output, relative to an economy with no credit market imperfections. The effects are exacerbated by a steepening of the term structure of interest rates that further encourages a shift towards short-term investments in the short-run. Small temporary shocks to the severity of financing frictions generate large and long-lasting effects on output through their impact on the composition of investment. A positive financial shock produces much stronger effects than an identical negative shock, while the responses to positive and negative shocks to aggregate productivity are roughly symmetric. Finally, the paper introduces a novel explanation for the countercyclicality of financing constraints of firms.Investment composition, Financial frictions, Business cycles, Idiosyncratic production risk, Firm heterogeneity

A probabilistic database extension

Data exchange between embedded systems and other small or large computing devices increases. Since data in different data sources may refer to the same real world objects, data cannot simply be merged. Furthermore, in many situations, conflicts in data about the same real world objects need to be resolved without interference from a user. In this report, we report on an attempt to make a RDBMS probabilistic, i.e., data in a relation represents all possible views on the real world, in order to achieve unattended data integration. We define a probabilistic relational data model and review standard SQL query primitives in the light of probabilistic data. It appears that thinking in terms of `possible worlds¿ is powerful in determining the proper semantics of these query primitives