Reliable a-posteriori error estimators for hphp-adaptive finite element approximations of eigenvalue/eigenvector problems

We present reliable a-posteriori error estimates for $hp$-adaptive finite element approximations of eigenvalue/eigenvector problems. Starting from our earlier work on $h$ adaptive finite element approximations we show a way to obtain reliable and efficient a-posteriori estimates in the $hp$-setting. At the core of our analysis is the reduction of the problem on the analysis of the associated boundary value problem. We start from the analysis of Wohlmuth and Melenk and combine this with our a-posteriori estimation framework to obtain eigenvalue/eigenvector approximation bounds.Comment: submitte

Estimating the Impact of Landfill Proximity on the Value of Real Estate Goods

A part of the net benefit from goods consumption is determined by their environmental characteristics. The size of the benefit depends on the properties of the goods, but also on how these are perceived by consumers. Therefore estimating environmental benefits allows, on the one hand, environment’s monetization, and on the other hand to formulate opinions about awareness regarding environmental issues and their impact on individual wellbeing. Departing from these facts, the paper aims to measure the environmental benefits of a real estate goods consumer, realizing an estimation of incompliant landfills (ICL) proximity’s impact on the value of these goods. For estimation, it was used the method of hedonic pricing and were processed regarding Bucharest periphery. Providing quantitative information regarding the importance of ecological criteria in the procurement of real estate goods, verification of the relevance of available estimations for Romania and the identification of the model that explains the impact of ICL on the value of real estate goods are the main contribution brought to knowledge development. In fact, the results obtained are aligned with the results of similar assessments made in Europe, indicating that 31,2% of the variation of real estate goods’ value is determined by the proximity of landfil. Studies regarding the relation between the size of variation and the development level could contribute to increase the relevance of these results for other regions of Romania.environmental benefits, hedonic prices, landfill, real estate goods, Bucharest periphery

D0-D8-F1 in Massive IIA SUGRA

We present some new supersymmetric solutions of massive IIA supergravity involving D0-branes, a D8-brane and a string. For the bosonic fields we use a general ansatz with SO(8) symmetry.Comment: 7 pages, reference added, appendix included in main tex

On velocities beyond the speed of light cc

From a mathematical point of view velocities can be larger than $c$. Lorentz transformations are easily extended in Minkowski space to discuss velocities beyond the speed of light. Energy and momentum conservation fixes the relation between masses and velocities larger than $c$, and some interesting consequences are drawn. Current data make neutrinos as possible candidates for having speed larger than $c$. Assuming this is true, a well known enigma on the arrival times of the neutrino bursts from the SN1987A supernova can be explained quite naturally. Finally, experimental research is proposed to verify the theory

Convergent adaptive finite element methods for photonic crystal applications

We prove the convergence of an adaptive finite element method for computing the band structure of 2D periodic photonic crystals with or without compact defects in both the TM and TE polarization cases. These eigenvalue problems involve non-coercive elliptic operators with discontinuous coefficients. The error analysis extends the theory of convergence of adaptive methods for elliptic eigenvalue problems to photonic crystal problems, and in particular deals with various complications which arise essentially from the lack of coercivity of the elliptic operator with discontinuous coefficients. We prove the convergence of the adaptive method in an oscillation-free way and with no extra assumptions on the initial mesh, beside the conformity and shape regularity. Also we present and prove the convergence of an adaptive method to compute efficiently an entire band in the spectrum. This method is guaranteed to converge to the correct global maximum and minimum of the band, which is a very useful piece of information in practice. Our numerical results cover both the cases of periodic structures with and without compact defects

Verso una riappropriazione collettiva dei beni ecclesiastici

Intervista a Daniela Ciaffi, vicepresidente di Labsus, l’associazione per la cura condivisa dei beni comuni.Gli immobili ecclesiastici in che modo possono essere intesi come beni comuni? Come valorizzarli e quale relazione intercorre tra gli immobili ecclesiastici e la comunità? Intervista in preparazione alla summer school Nuovi scenari per patrimoni monastici dismessi, Lucca luglio 2019

Solving elliptic eigenvalue problems on polygonal meshes using discontinuous Galerkin composite finite element methods

In this paper we introduce a discontinuous Galerkin method on polygonal meshes. This method arises from the discontinuous Galerkin composite finite element method (DGFEM) for source problems on domains with micro-structures. In the context of the present paper, the flexibility of DGFEM is applied to handle polygonal meshes. We prove the a priori convergence of the method for both eigenvalues and eigenfunctions for elliptic eigenvalue problems. Numerical experiments highlighting the performance of the proposed method for problems with discontinuous coefficients and on convex and non-convex polygonal meshes are presented