The edge-based strain smoothing method for compressible and nearly incompressible non-linear elasticity for solid mechanics

E-print/Working paper (in press)

Endogenous Working Hours, Overlapping Generations and Balanced Neoclassical Growth

E-print/Working paper (2023)

A balanced growth path that accounts for a decline in hours worked per worker approximates the evolution of today’s industrialized countries since 1870. This stylized fact is explained in an OLG-model ... [more ▼]

A balanced growth path that accounts for a decline in hours worked per worker approximates the evolution of today’s industrialized countries since 1870. This stylized fact is explained in an OLG-model featuring two-period lived individuals equipped with per-period utility functions of the generalized loglog type proposed by Boppart and Krusell (2020) and a neoclassical production sector. Technological progress drives real wages up and expands the amount of consumption goods. The value of leisure increases, and the supply of hours worked declines. Technological progress moves a poor economy out of a regime with low wages and an inelastic supply of hours worked into a regime with high wages and a declining supply of hours worked. The balanced growth path is unique and stable. In the high wage regime, the equilibrium difference equation is available in closed form. A balanced growth path with declining hours worked may also be obtained with endogenous technological progress as in Romer (1986). [less ▲]

Physical Activity, Dietary Consumption and Weight Status of school aged children

E-print/Working paper (2023)

Key findings: Boys are more physically active than girls. Girls consume vegetables daily more frequently than boys. Prevalence of overweight and obesity is higher for boys than for girls.

Critical Mineral Depletion and Recycling: From the Perspective of the Cooperation and Open-Loop Competition

E-print/Working paper (2023)

Critical minerals are essential to the success of the transition to clean and sustainable technology. However, critical minerals face supply chain disruption, resource depletion, a lack of recycling ... [more ▼]

Critical minerals are essential to the success of the transition to clean and sustainable technology. However, critical minerals face supply chain disruption, resource depletion, a lack of recycling technology and minimum demand, which may be increasing over time, at least in the short run. This paper models critical mineral extraction and recycling strategies under international cooperation and open-loop commitment competition. We show that (1) recycling technology can only partially reduce dependence on the virgin supply of critical minerals, given that recycling essentially relies on the accumulated supply from depletable resources; (2) the social planner's Markovian optimal market supply is based on either virgin or recyclable resources, with the more socially desirable being used first; (3) if the recyclable resource is exhausted, the social planner does not have an optimal choice regarding how to exploit the remaining virgin resource; but (4) under open-loop commitment, the two resources can coexist until the virgin resource is exhausted. [less ▲]

Optimal Timing of Carbon-Capture Policies Among Di erent Countries Under Markovian Competition

E-print/Working paper (2023)

Carbon capture and storage (CCS) is considered one of the most important and efficient tools in fighting against greenhouse gas emissions. Countries differ in terms of the level CCS processes implemented ... [more ▼]

Carbon capture and storage (CCS) is considered one of the most important and efficient tools in fighting against greenhouse gas emissions. Countries differ in terms of the level CCS processes implemented, with the main barrier to CCS adoption being its high cost. This paper introduces a differential game model with heterogeneous countries to investigate the optimal timing for countries to initiate CCS projects, taking into account CCS costs. We show that (i) the thresholds for the triggering of CCS projects depend not only on one's own CCS costs but also those of others, in addition to the pollution damage costs; (ii) the optimal timing for different countries to initiate their CCS projects is the moment when their threshold level of pollution stock is reached; (iii) countries are more inclined to free-ride by both reducing pollutant emissions and deploying CCS when pollution damage costs are symmetric rather than asymmetric; finally, (iv) we provide sufficient conditions under which some countries never deploy CCS even though they bear the same pollution damage as the others. [less ▲]

Multifractional Hermite processes: definition and first properties

E-print/Working paper (2023)

We define multifractional Hermite processes which generalize and extend both multifractional Brownian motion and Hermite processes. It is done by substituting the Hurst parameter in the definition of ... [more ▼]

We define multifractional Hermite processes which generalize and extend both multifractional Brownian motion and Hermite processes. It is done by substituting the Hurst parameter in the definition of Hermite processes as a multiple Wiener-Itô integral by a Hurst function. Then, we study the pointwise regularity of these processes, their local asymptotic self-similarity and some fractal dimensions of their graph. Our results show that the fundamental properties of multifractional Hermite processes are, as desired, governed by the Hurst function. Complements are given in the second order Wiener chaos, using facts from Malliavin calculus. [less ▲]

Adressing the ‘winner-takes-all’ character of sustainability taxonomies

E-print/Working paper (2023)

Tropical Backpropagation

E-print/Working paper (2023)

This work introduces tropicalization, a novel technique that delivers tropical neural networks as tropical limits of deep ReLU networks. Tropicalization transfers the initial weights from real numbers to ... [more ▼]

This work introduces tropicalization, a novel technique that delivers tropical neural networks as tropical limits of deep ReLU networks. Tropicalization transfers the initial weights from real numbers to those in the tropical semiring while maintain- ing the underlying graph of the network. After verifying that tropicalization will not affect the classification capacity of deep neural networks, this study introduces a tropical reformulation of backpropagation via tropical linear algebra. Tropical arithmetic replaces multiplication operations in the network with additions and addition operations with max, and therefore, theoretically, reduces the algorithmic complexity during the training and inference phase. We demonstrate the latter by simulating the tensor multiplication underlying the feed-forward process of state- of-the-art trained neural network architectures and compare the standard forward pass of the models with the tropical ones. Our benchmark results show that tropi- calization speeds up inference by 50 %. Hence, we conclude that tropicalization bears the potential to reduce the training times of large neural networks drastically. [less ▲]

Historian cultures – the epistemology and methodology of history in the digital age - CulturHist

E-print/Working paper (2023)

CulturHist has its sights particularly on the community of researchers, who have done little to make the results and suggestions offered by the digital humanities their own. We want to focus the ... [more ▼]

CulturHist has its sights particularly on the community of researchers, who have done little to make the results and suggestions offered by the digital humanities their own. We want to focus the discussion on a cross cutting issue: the link to archives, as the raw material for writing an account of the past. The habit of working digitally of those historians who do not nowadays verbalise their computer practices is now widespread and is bolstered by policies aimed at making many digitised document collections available online. For example, a search using the Internet Archive wayback machine developed by a not-for-profit company which archives the Web, shows that, in January 2002, Gallica, the digital library of the Bibliothèque Nationale de France (National Library of France), reported having 80 000 documents online, as compared to a little over 5.8 million on 4 September 2019. These days, it is possible to carry out international historical investigations without being in physical contact with a document, as was demonstrated as far back as 2011 by the Data mining with criminal intent project (Cohen et al.). This means that researchers often become data managers (Cartier et al.). Most researchers now practise these habits, and there is an urgent need to analyse them and adapt initial and further training in history in order to help students and historians grasp how ways of writing history are being changed. [less ▲]

Estimator selection for regression functions in exponential families with application to changepoint detection

E-print/Working paper (2023)

Is Bitcoin a better safe-haven asset for individual investors than Gold? – Evidence from sanctioned Russia

E-print/Working paper (2022)

Extensive research on safe-haven assets has been conducted in the literature. An important finding is that safe-haven assets are frequently used by institutional investors, such as pension funds and ... [more ▼]

Extensive research on safe-haven assets has been conducted in the literature. An important finding is that safe-haven assets are frequently used by institutional investors, such as pension funds and investment banks, to ride out high volatility. However, the issue of whether individual investors can benefit from it during a financial crisis has not been adequately addressed. Using the case of sanctioned Russia, we attempt to study whether Bitcoin as a decentralized asset can play a more useful role than gold to protect individual investors when the majority of safe-haven assets are restricted from transactions. Our main results show that both assets exhibit intraday weak safe-haven properties against the ruble. However, gold saw a waning trend compared with its historical performance, whereas Bitcoin’s capability increased during this period. Further sentiment analysis demonstrates Russian investors’ positive attitudes regarding Bitcoin boosting its price in response to the ruble’s depreciation. The return on gold is more likely to be impacted by international investors who are concerned about global uncertainties. [less ▲]

Optimal coalition splitting with heterogenous strategies

E-print/Working paper (2022)

We consider a group of players initially members of a coalition managing cooperatively a public bad, in this case, the stock of pollution. Countries are technologically heterogeneous but the pollution ... [more ▼]

We consider a group of players initially members of a coalition managing cooperatively a public bad, in this case, the stock of pollution. Countries are technologically heterogeneous but the pollution damage is uniform. We essentially attempt to characterize the conditions under which a country may eventually split and when it splits within an infinite horizon multi-stage differential game. In contrast to the existing literature, we do not assume that after splitting, the splitting player and the remaining coalition will adopt Markovian strategies. Instead, we assume that the latter will remain committed to the collective control of pollution and play open-loop, while the splitting player plays Markovian. Within a full linear-quadratic model, we characterize the optimal strategies. We later compare with the outcomes of the case where the splitting player and the remaining coalition play both Markovian. We highlight several interesting results in terms of the implications for long- term pollution levels and the duration of coalitions with heterogeneous strategies. [less ▲]

A dynamic programming approach to optimal pollution control under uncertain irreversibility: The Poisson case

E-print/Working paper (2022)

We solve a bimodal optimal control problem with a non-concavity and uncertainty through a Poisson process underlying the transition from a mode to another. We use a dynamic programming approach and are ... [more ▼]

We solve a bimodal optimal control problem with a non-concavity and uncertainty through a Poisson process underlying the transition from a mode to another. We use a dynamic programming approach and are able to uncover the global optimal dynamics (including optimal non-monotonic paths) under a few linear-quadratic assumption, which do not get rid of the non-concavity of the problem. This is in contrast to the related literature on pollution control under irreversibility which usually explores local dynamics along monotonic solution paths to first order Pontryagin conditions. [less ▲]

Deep Learning for Ground and Non-ground Surface Separation: A Feature-based Semantic Segmentation Algorithm for Point Cloud Classification

E-print/Working paper (2022)

Precise ground surface topography is crucial for 3D city analysis, digital terrain modeling, natural disaster monitoring, high-density map generation, and autonomous navigation to name a few. Deep ... [more ▼]

Precise ground surface topography is crucial for 3D city analysis, digital terrain modeling, natural disaster monitoring, high-density map generation, and autonomous navigation to name a few. Deep learning (DL; LeCun, et al., 2015), a division of machine learning (ML), has been achieving unparalleled success in image processing, and recently demonstrated a huge potential for point cloud analysis. This article presents a feature-based DL algorithm that classifies ground and non-ground points in aerial laser scanning point clouds. Recent advancements of remote sensing technologies make it possible digitizing the real world in a near automated fashion. LiDAR (Light Detection and Ranging) based point clouds that are a type of remotely sensed georeferenced data, providing detailed 3D information on objects and environment have been recognized as one of the most powerful means of digitization. Unlike imagery, point clouds are unstructured, sparse and of irregular data format which creates many challenges, but also provides huge opportunities for capturing geometric details of scanned surfaces with millimeter accuracy. Classifying and separating non-ground points from ground points largely reduce data volumes for consecutive analyses of either ground or non-ground surfaces, which consequently saves cost and labor, and simplifies further analysis. [less ▲]

Why and when coalitions split? An alternative analytical approach with an application to environmental agreements

E-print/Working paper (2022)

We use a parsimonious two-stage differential game setting where the duration of the first stage, the coalition stage, depends on the will of a particular player to leave the coalition through an explicit ... [more ▼]

We use a parsimonious two-stage differential game setting where the duration of the first stage, the coalition stage, depends on the will of a particular player to leave the coalition through an explicit timing variable. By specializing in a standard linear-quadratic environmental model augmented with a minimal constitutional setting for the coalition (payoff share parameter), we are able to analytically extract several nontrivial findings. Three key aspects drive the results: the technological gap as an indicator of heterogeneity across players, the constitution of the coalition and the intensity of the public bad (here, the pollution damage). We provide with a full analytical solution to the two-stage differential game. In particular, we characterize the intermediate parametric cases leading to optimal nite time splitting. A key characteristic of these finite-time-lived coalitions is the requirement of the payoff share accruing to the splitting country to be large enough. Incidentally, our two-stage differential game setting reaches the conclusion that splitting countries are precisely those which use to benefit the most from the coalition. Constraining the payoff share to be low by Constitution may lead to optimal everlasting coalitions only provided initial pollution is high enough, which may cover the emergency cases we are witnessing nowadays. [less ▲]

Finite Mixture Models for an underlying Beta distribution with an application to COVID-19 data

E-print/Working paper (2022)

Pandemic Impacts on Sustainability and Hartwick’s Rule

E-print/Working paper (2022)

In this study, we present a modified Hartwick rule encompassing the dynamics of pandemic, such as COVID-19. In our setting, the labor productivity gradually improves after the pandemic shock and may even ... [more ▼]

In this study, we present a modified Hartwick rule encompassing the dynamics of pandemic, such as COVID-19. In our setting, the labor productivity gradually improves after the pandemic shock and may even go beyond its pre-pandemic level due to the remote work and digitalization as also suggested by the empirical evidence. We demonstrate that a gradual labor productivity increase helps to conserve natural resources. We provide a theoretical foundation for a“sooner-the-better" strategy to control a pandemic, and we show that policy maker should implement a “whatever it costs” response to ensure that the transmission rate of the virus is below the recovery rate from the very beginning of the pandemic. Otherwise, the economy cannot have a sustained utility. We also analyze the implications of an “uncertain” pandemic on the intertemporal dynamics of natural resource and capital accumulation under the maximin criterion. Another important finding is that there exists a new economic and public health trade-off since a strong prevention policy is shown to decrease capital accumulation. [less ▲]

FINCITY -- Excerpt from project description

E-print/Working paper (2022)

Der Arbeitsmarkt der Sozialen Arbeit 2020 = Le marché de l'emploi du secteur social en 2020

E-print/Working paper (2022)

Dieser Newsletter beschreibt den Arbeitsmarkt der Sozialen Arbeit in Luxemburg 2020 und die Entwicklung der Zahlen in einigen Bereichen für 2018 bis 2020. Die Daten stammen von einem fortlaufenden ... [more ▼]

Dieser Newsletter beschreibt den Arbeitsmarkt der Sozialen Arbeit in Luxemburg 2020 und die Entwicklung der Zahlen in einigen Bereichen für 2018 bis 2020. Die Daten stammen von einem fortlaufenden Forschungsprojekt des PraxisBüros der Universität Luxemburg. Der Newsletter stellt eine Auswahl an Statistiken dar, z.B. bezüglich der meist gefragten Qualifikationsniveaus, der Verteilung der Praxisfelder, der Verteilung der Stellenangebote zwischen öffentlichen, kommunalen, gemeinnützigen und privaten Trägern und der erfassten enormen Diskrepanz zwischen Nachfrage und Angebot an qualifizierten Professionellen in der Sozialen Arbeit. Desweiteren werden Entwicklungstrends- vor allem zu Thema Aus- und Weiterbildung aufgezeigt. [less ▲]

A restless badit approach for capacitated condition based maintenance scheduling

E-print/Working paper (2022)

Building Regional Payment Areas: The Single Rule Book Approach

E-print/Working paper (2022)

A topological Paley-Wiener-Schwartz Theorem for sections of homogeneous vector bundles on G/K

E-print/Working paper (2022)

We study the Fourier transform for compactly supported distributional sections of complex homogeneous vector bundles on symmetric spaces of non-compact type X = G/K. We prove a characterisation of their ... [more ▼]

We study the Fourier transform for compactly supported distributional sections of complex homogeneous vector bundles on symmetric spaces of non-compact type X = G/K. We prove a characterisation of their range. In fact, from Delorme’s Paley-Wiener theorem for compactly supported smooth functions on a real reductive group of Harish-Chandra class, we deduce topological Paley-Wiener and Paley-Wiener- Schwartz theorems for sections. [less ▲]

DLT-Based Enhancement of Cross-Border Payment Efficiency – a Legal and Regulatory Perspective

E-print/Working paper (2022)

The Tor Spectral Sequence and Flat Morphisms in Homotopical D-Geometry

E-print/Working paper (2022)

TRADE SECRET PROTECTION AND R&D INVESTMENT OF FAMILY FIRMS

E-print/Working paper (2022)

The Impact of the Asset Purchase Programme on Systemic Risk in the Euro Area: Is There a Threat?

E-print/Working paper (2021)

Diversity on the screen

E-print/Working paper (2021)

Requirements And Threat Models of Adversarial Attacks and Robustness of Chest X-ray classification

E-print/Working paper (2021)

Vulnerability to adversarial attacks is a well-known weakness of Deep Neural Networks. While most of the studies focus on natural images with standardized benchmarks like ImageNet and CIFAR, little ... [more ▼]

Vulnerability to adversarial attacks is a well-known weakness of Deep Neural Networks. While most of the studies focus on natural images with standardized benchmarks like ImageNet and CIFAR, little research has considered real world applications, in particular in the medical domain. Our research shows that, contrary to previous claims, robustness of chest x-ray classification is much harder to evaluate and leads to very different assessments based on the dataset, the architecture and robustness metric. We argue that previous studies did not take into account the peculiarity of medical diagnosis, like the co-occurrence of diseases, the disagreement of labellers (domain experts), the threat model of the attacks and the risk implications for each successful attack. In this paper, we discuss the methodological foundations, review the pitfalls and best practices, and suggest new methodological considerations for evaluating the robustness of chest xray classification models. Our evaluation on 3 datasets, 7 models, and 18 diseases is the largest evaluation of robustness of chest x-ray classification models. We believe our findings will provide reliable guidelines for realistic evaluation and improvement of the robustness of machine learning models for medical diagnosis. [less ▲]

A global carbon tax? Why firm mobility and heterogeneity matters

E-print/Working paper (2021)

Evaluation of TPMS Signal Propagation in a Heavy Commercial Vehicle Environement

E-print/Working paper (2021)

Covid-Kids II. Survey for children aged 6 to 16 about their experiences during the Covid-19 pandemic

E-print/Working paper (2021)

The good, the bad, and the asymmetric: Evidence from a new conditional density model

E-print/Working paper (2021)

We propose a novel univariate conditional density model and decompose asset returns into a sum of copula-connected unobserved ‘good’ and ‘bad’ shocks. The novelty of this approach comes from two factors ... [more ▼]

We propose a novel univariate conditional density model and decompose asset returns into a sum of copula-connected unobserved ‘good’ and ‘bad’ shocks. The novelty of this approach comes from two factors: we explicitly model correlation between unobserved shocks and allow for the presence of copula-connected discrete jumps. The proposed framework is very flexible and subsumes other models, such as ‘bad environments, good environments’. Our model shows certain hidden characteristics of returns, explains investors’ behaviour in greater detail, and yields better forecasts of risk measures. The in-sample and out-of-sample performance of our model is better than that of 40 popular GARCH variants. A Monte-Carlo simulation shows that the proposed model recovers the structural parameters of the unobserved dynamics. We estimate the model on S&P 500 data and find that time-dependent non-negative covariance between ‘good’ and ‘bad’ shocks with a leverage-like effect is an important component of total variance. Asymmetric reaction to shocks is present almost in all characteristics of returns. Conditional distribution of seems to be very time-dependent with skewness both in the centre and tails. We conclude that continuous shocks are more important than discrete jumps at least at daily frequency. [less ▲]

Adaptively Secure Laconic Function Evaluation for NC1

E-print/Working paper (2021)

Cloturing Deliberation

E-print/Working paper (2021)

We study how the institutional arrangements for ending deliberation --- the "cloture rules" --- interact with collective learning to affect the outcomes of decision making in committees. In contrast to ... [more ▼]

We study how the institutional arrangements for ending deliberation --- the "cloture rules" --- interact with collective learning to affect the outcomes of decision making in committees. In contrast to much of the previous literature on deliberative commit tees, this paper makes a distinction between the final votes over policy proposals and the cloture votes that bring them about. Using this approach, we explore how cloture rules influence the course of deliberation, the likelihood of inefficient deliberative outcomes, the circumstances surrounding failures to bring proposals to a final vote, and the distribution of power among committee members in the deliberative process. We also use our simple model to examine the issue of the stability of cloture rules, characterizing the rules that no coalition of committee members is able or willing to overturn. We show in particular that all cloture rules are dynamically stable. [less ▲]

Cultural differences and immigrants' wages

E-print/Working paper (2021)

In this paper, I investigate how cultural differences affect the labor-market performance of immigrant workers in Germany. I document a negative relationship between hourly wages and the cultural distance ... [more ▼]

In this paper, I investigate how cultural differences affect the labor-market performance of immigrant workers in Germany. I document a negative relationship between hourly wages and the cultural distance between immigrants' countries of origin and Germany. This result is robust across the three main indicators used in the gravity literature: linguistic, religious, and genetic distances. This cultural wage penalty disappears after five to ten years spent in Germany. Controlling for language proficiency as well as for selective in- and out-migration, these results highlight the cultural integration of immigrant workers. I finally provide evidence suggesting that lower wage progression may be explained by fewer job-to-job transitions. [less ▲]

Environmental Culture and Economic Complexity

E-print/Working paper (2021)

Strategic Behavior in a Serial Newsvendor Setting

E-print/Working paper (2021)

Post-Quantum Secure LFE for L/poly with Smaller Parameters

E-print/Working paper (2021)

The Long-Term Effect of Research Grants on the Scientific Output of University Professors

E-print/Working paper (2021)

De la guerre civile du 16e siècle à la "guerre idéologique" du 19e siècle. La réception de la Révolte des Pays-Bas en Belgique

E-print/Working paper (2021)

From Centralized to Decentralized Finance: The Issue of “Fake-DeFi”

E-print/Working paper (2021)

COVID Stress Test for the Rule of Law: States of Emergency under International Human Rights Law

E-print/Working paper (2021)

Les reliques des "martyrs de Gorcum" à Bruxelles

E-print/Working paper (2021)

Common pool resource management and risk perceptions

E-print/Working paper (2020)

Motivated by recent discussions about the issue of risk perceptions for climate change related events, we introduce a non-cooperative game setting where agents manage a common pool resource under a ... [more ▼]

Motivated by recent discussions about the issue of risk perceptions for climate change related events, we introduce a non-cooperative game setting where agents manage a common pool resource under a potential risk, and agents exhibit different risk perception biases. Focusing on the effect of the polarization level and other population features, we show that the type of bias (overestimation versus underestimation biases) and the resource quality level before and after the occurrence of the shift have first-order importance on the qualitative nature of behavioral adjustments and on the pattern of resource conservation. When there are non-uniform biases within the population, the intra-group structure of the population qualitatively affects the degree of resource conservation. Moreover, unbiased agents may react in nonmonotone ways to changes in the polarization level when faced with agents exhibiting different types of bias. The size of the unbiased agents’ sub-population does not qualitatively affect how an increase in the polarization level impacts individual behavioral adjustments, even though it affects the magnitude of this change. Finally, it is shown how perception biases affect the comparison between centralized and decentralized management. [less ▲]

Linear Z2n-Manifolds and Linear Actions

E-print/Working paper (2020)

The Luxembourg COVID-Kids questionnaire

E-print/Working paper (2020)

Dynamics of Achievement inequalities: the role of performance and choice in Chile

E-print/Working paper (2020)

Research on education inequalities has long-established the relationship between the social composition of of schools and achievement levels. However, the empirical study of the social processes in ... [more ▼]

Research on education inequalities has long-established the relationship between the social composition of of schools and achievement levels. However, the empirical study of the social processes in choosing schools and their potential effects on achievement inequalities has often been neglected. This article investigates the extent to which such social processes, related to parents’ educational preferences and expectations, influence the development of students’ achievement inequalities throughout their schooling career, through shaping school communities, as a channel of transmission of socioeconomic inequality. Using longitudinal census data from Chile, which allows us to observe students’ achievements between the 4th and 10th grades, we find support for the claim that the development of achievement inequalities operate partly through well-off parents’ educational preferences and expectations. Moreover, these preferences and beliefs explain most of the social composition effect of schools on achievement inequalities. We conclude that choice processes should be considered as an integral part of theories aimed to explain achievement inequalities as a dynamic process. [less ▲]

The Lehman Sisters Claim

E-print/Working paper (2020)

I evaluate Christine Lagarde´s claim that more female leaders can be associated with more prudence, and less of the risky decision-making that had provoked the crisis. Indeed, the proportion of women who ... [more ▼]

I evaluate Christine Lagarde´s claim that more female leaders can be associated with more prudence, and less of the risky decision-making that had provoked the crisis. Indeed, the proportion of women who are employed in decision-making and management roles in governments, large enterprises and institutions varies substantially across European countries and is oftentimes below 30%. Research suggests that in addition to biological differences, men and women show morphological dissimilarities in specific brain regions, which explain the observed differences in behavior. As a result, female decision makers tend to be more risk averse, better suited to carefully analyze a problem, superior in multitasking and better in creating solutions that work for a group. Not surprisingly, firms with more female decision makers tend to outperform their peers in terms of productivity, profitability and stock performance while taking fewer risks. In this paper, I aim to explore the effect of female decision making on aggregate equity returns. Relying on an equilibrium asset-pricing model in an economy under jump diffusion, I decompose the moments of the returns of European stock market indices into a diffusive (systematic) risk and an (idiosyncratic) extreme event risk part. For a balanced panel of European countries, I find empirical evidence for a Lehman sisters’ effect: female decision making is an important determinant of (idiosyncratic) extreme event risk. As a result, stock markets in countries with more female decision makers are characterized by higher risk aversion, lower volatility and more positive return asymmetry, primarily driven by extreme event risk, e.g. the lower frequency of negative jumps. Results are robust to the inclusion of various controls for other country- or market-specific characteristics. [less ▲]

Deniable encryption, authentication, and key exchange

E-print/Working paper (2020)

We present some foundational ideas related to deniable encryption, message authentication, and key exchange in classical cryptography. We give detailed proofs of results that were previously only sketched ... [more ▼]

We present some foundational ideas related to deniable encryption, message authentication, and key exchange in classical cryptography. We give detailed proofs of results that were previously only sketched in the literature. In some cases, we reach the same conclusions as in previous papers; in other cases, the focus on rigorous proofs leads us to different formulations of the results. [less ▲]

Optimized Collision Search for STARK-Friendly Hash Challenge Candidates

E-print/Working paper (2020)

In this note, we report several solutions to the STARK-Friendly Hash Challenge: a competition with the goal of finding collisions for several hash functions designed specifically for zero-knowledge proofs ... [more ▼]

In this note, we report several solutions to the STARK-Friendly Hash Challenge: a competition with the goal of finding collisions for several hash functions designed specifically for zero-knowledge proofs (ZKP) and multiparty computations (MPC). We managed to find collisions for 3 instances of 91-bit hash functions. The method used is the classic parallel collision search with distinguished points from van Oorshot and Wiener (1994). As this is a general attack on hash functions, it does not exhibit any particular weakness of the chosen hash functions. The crucial part is to optimize the implementations to make the attack cost realistic, and we describe several arithmetic tricks. [less ▲]