On the monotonicity of perimeter of convex bodies

Let $n\ge2$ and let $\Phi\colon\mathbb{R}^n\to[0,\infty)$ be a positively $1$-homogeneous and convex function. Given two convex bodies $A\subset B$ in $\mathbb{R}^n$, the monotonicity of anisotropic $\Phi$-perimeters holds, i.e. $P_\Phi(A)\le P_\Phi(B)$. In this note, we prove a quantitative lower bound on the difference of the $\Phi$-perimeters of $A$ and $B$ in terms of their Hausdorff distance.Comment: 8 page

On human dignity and State sovereignty: The Italian Constitutional Court's 238/2014 judgment on State immunity for international crimes

Judgment 238/2014 of the Italian Constitutional Court has flatly contravened the decision of the ICJ on Jurisdictional Immunity of States (Germany v. Italy: Greece intervening) of 2012, ruling that the customary norm on State immunity from civil suits before a foreign court as ascertained in the ICJ decision never entered the domestic legal order, because it is incompatible with core principles of the Italian Constitution. In execution of the Constitutional Court ruling, in 2015, some Italian tribunals have condemned Germany to pay damages to former Italian military internees victim of international crimes during World War II, thus integrating an international wrongful act on the part of Italy. The 238/2014 judgment has been criticised from many angles. Much criticism was addressed to its alleged dualist approach that seemed to insulate Italy. The paper argues that the 2014 judgment of the Italian court is rather a reasoned response to the ICJ decision, grounded on principles common to the Italian and the international law, and a call for a consistent application of State obligations concerning the effective implementation of human rights. From this perspective it constitutes a valuable contribution towards a principled and open-minded debate over the structure and function of international la

Products of ideals may not be Golod

We exhibit an example of a product of two proper monomial ideals such that the residue class ring is not Golod. We also discuss the strongly Golod property for rational powers of monomial ideals, and introduce some sufficient conditions for weak Golodness of monomial ideals. Along the way, we ask some related questions.Comment: 18 pages, minor changes from first versio

Improved Lipschitz approximation of HH-perimeter minimizing boundaries

We prove two new approximation results of $H$-perimeter minimizing boundaries by means of intrinsic Lipschitz functions in the setting of the Heisenberg group $\mathbb{H}^n$ with $n\ge2$. The first one is an improvement of a result of Monti and is the natural reformulation in $\mathbb{H}^n$ of the classical Lipschitz approximation in $\mathbb{R}^n$. The second one is an adaptation of the approximation via maximal function developed by De Lellis and Spadaro.Comment: 25 page

Labour Market Outcomes of Second Generation Immigrants: How Heterogeneous Are They Really?

The second and third generation of immigrants have been the centre of a lively debate about the economic integration of immigrants into their host societies, but there is little empirical evidence on the German case. In this study I comprehensively portray the labour market outcomes of second generation immigrants in Germany. Special attention is attributed to observable heterogeneity in terms of country of origin and unobservable heterogeneity in terms of parental human capital, neighbourhood effects, and mixed marriage background. Pooled, static and dynamic panel data models, and a decomposition analysis are used to estimate and explain the average differences in hourly wages and unemployment probabilities separately for men and women. The results suggest that the second generation cannot be considered as one homogeneous group; some groups perform better, equally or worse than comparable German natives. Also, relative outcomes in wages depend mainly on observable characteristics, whereas relative unemployment risks are mainly driven by unobservable factors.Panel data, second generation immigrants, labour market outcomes, random effects, dynamic models, decomposition analysis

The EU Budget and Common Agricultural Policy Beyond 2020: Seven More Years of Money for Nothing? Bertelsmann Shiftung Reflection Paper No. 3 August 2018

At the outset of European integration, farming featured high on the political agenda for good reason: the food security of postwar Europe was at stake. But by the 1980s, subsidies to agriculture still accounted for two-thirds of the EU budget. Today, the Common Agricultural Policy (CAP) accounts for roughly 38 percent of spending, the largest single expenditure in the Multiannual Financial Framework (MFF). According to the new Commission pro-posal for the MFF 2021–2027, this will change only slightly. Direct payments to farmers will still constitute the largest item in the CAP budget. This analysis looks into the two main arguments for legitimizing CAP: income protection and European public goods. Our proposal for reform starts from the premise that income protection cannot justify the current level of direct payment from the EU budget. Likewise, the public good justification, which gained substantial rhetoric im-portance in the MFF 2014–2020, has not come to fruition. Evidence indicates that “greening conditions”, set up to protect the environment, have been largely non-binding, unproductive, and thus an unjustifiable expense. Against this backdrop, the Commission’s June 2018 proposal on CAP’s future is disappointing. We conclude that the current proposal is not in line with a sound public goods approach. Without substantial modification, direct payments will remain an ineffective incentive for the provision of agricultural services in the fields of environment, climate policy, and animal protection. In the Commission proposal, the instrument of “eco-schemes” comes closest to a model of public goods-related direct payments. In coming months, there are still opportunities to improve the draft. We rec-ommend that in the future budget a certain share of direct payments – up to 50 percent of national envelopes – is spent on eco-schemes that should reflect a strict “value-for-money” rationale. Eco-schemes would then define compensation for the verified provision of public goods at well-defined unit prices

The referendum incentive compatibility hypothesis: Some new results using information messages

We report results from a laboratory experiment that allows us to test the incentive compatibility hypothesis of hypothetical referenda used in CV studies through the public or private provision of information messages. One of the main methodological issues about hypothetical markets regards whether people behave differently when bidding for a public good through casting a ballot vote than when they are privately purchasing an equivalent good. This study tried to address the core of this issue by using a good that can be traded both as private and public: information messages. This allows the elimination of confounding effects associated with the specific good employed. In our case information dispels some of the uncertainty about a potential gain from a gamble. So, the approximate value of the message can be inferred once the individual measure of risk aversion is known. Decision tasks are then framed in a systematic manner according to the hypothetical vs real nature of the decision and the public vs private nature of the message. A sample of 536 university students across three countries (I, UK and NZ) participated into this lab experiment. The chosen countries reflect diversity in exposure to the practice of advisory (NZ) and abrogative (Italy) referenda, with the UK not having any exposure to it. Under private provision the results show that the fraction of participants unwilling to buy information is slightly higher in the real treatment than in the hypothetical one. Under public provision, instead, there is no statistical difference between real and hypothetical settings, confirming in part the finding of previous researchers. A verbal protocol analysis of the thought processes during choice highlights that public provision of information systematically triggers concerns and motivations different from those arising under the private provision setting. These findings suggest that the incentive compatibility of public referenda is likely to rely more on affective and psychological factors than on the strategic behaviour assumptions theorised by economists

Linking dissipation-induced instabilities with nonmodal growth: the case of helical magnetorotational instability

The helical magnetorotational instability is known to work for resistive rotational flows with comparably steep negative or extremely steep positive shear. The corresponding lower and upper Liu limits of the shear are continuously connected when some axial electrical current is allowed to flow through the rotating fluid. Using a local approximation we demonstrate that the magnetohydrodynamic behavior of this dissipation-induced instability is intimately connected with the nonmodal growth and the pseudospectrum of the underlying purely hydrodynamic problem.Comment: 5 pages, 4 figure