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ORBi

Z_2^n-Supergeometry I: Manifolds and Morphisms Covolo, Tiffany ; ; Poncin, Norbert E-print/Working paper (2014) Detailed reference viewed: 269 (73 UL)D’méisproochegt Gehir Engel de Abreu, Pascale E-print/Working paper (2014) Den „kognitive Virdeel“ vun der Méisproochegkeet besteet doranner, datt méisproocheg Kanner a bestëmmte kognitiven Aufgaben, déi déi sougenannten „Exekutivfunktioune“ moossen, besser si wéi Kanner, déi ... [more ▼] Den „kognitive Virdeel“ vun der Méisproochegkeet besteet doranner, datt méisproocheg Kanner a bestëmmte kognitiven Aufgaben, déi déi sougenannten „Exekutivfunktioune“ moossen, besser si wéi Kanner, déi nëmmen eng Sprooch schwätzen. [less ▲] Detailed reference viewed: 141 (9 UL)Is there a Bubble in the Art Market? Kräussl, Roman ; Lehnert, Thorsten ; E-print/Working paper (2014) Detailed reference viewed: 1201 (82 UL)Risk and Expected Returns of Private Equity Investments: Evidence Based on Market Prices Kräussl, Roman ; ; E-print/Working paper (2014) Detailed reference viewed: 109 (0 UL)News Media Sentiment and Investor Behavior Kräussl, Roman ; E-print/Working paper (2014) Detailed reference viewed: 16 (0 UL)A very good triple of operads Riviere, Salim E-print/Working paper (2013) Detailed reference viewed: 53 (0 UL)Leitfaden wissenschaftliches Arbeiten - Wie schreibe ich eine Hausarbeit und wie präsentiere ich sie? Heinz, Andreas ; ; E-print/Working paper (2013) Detailed reference viewed: 527 (24 UL)Product Unbundling in the Travel Industry: The Economics of Airline Bag Fees ; ; Picard, Pierre M et al E-print/Working paper (2013) This paper provides theory and evidence on airline bag fees, offering insights into a real-world case of product unbundling. The theory predicts that an airline’s fares should fall when it introduces a ... [more ▼] This paper provides theory and evidence on airline bag fees, offering insights into a real-world case of product unbundling. The theory predicts that an airline’s fares should fall when it introduces a bag fee, but that the full trip price (the bag fee plus the new fare) could either rise or fall. The empirical evidence presented in the paper provides strong confirmation of this prediction. The data also suggest that the average fare falls by less than the bag fee itself, so that the full price of a trip rises for passengers who choose to check bags. [less ▲] Detailed reference viewed: 78 (15 UL)Timeliness in Selected Structural Credit Risk Models Jin, Xisong ; Lehnert, Thorsten ; E-print/Working paper (2013) We empirically investigate and evaluate various approaches to structurally assess credit risk changes using a panel of selected European banking groups. The objective is to evaluate the models according ... [more ▼] We empirically investigate and evaluate various approaches to structurally assess credit risk changes using a panel of selected European banking groups. The objective is to evaluate the models according to one metric, i.e., their ability to correctly and timely identify changes in credit risk indicators useful for macroprudential policy. We consider not only the standard approaches in the literature, but also include models that allow the asset volatility to be stochastic and models that allow for short- and long-term components of default risk. Surprisingly, we find that the GARCH structural credit risk model, despite its more sophisticated modeling approach, typically underperforms more basic models. Importantly for macro-prudential policy, combining the Merton model with the GARCH-MIDAS model performs best and reflects important market events earlier than the other approaches. [less ▲] Detailed reference viewed: 77 (1 UL)Does it Pay to Invest in Art? A Selection-corrected Returns Perspective Kräussl, Roman ; ; E-print/Working paper (2013) Detailed reference viewed: 102 (11 UL)The Effect of Anticipated and Experienced Regret and Pride on Investors’ Future Selling Decisions* Kräussl, Roman ; ; E-print/Working paper (2013) Detailed reference viewed: 64 (1 UL)Das mehrsprachige Gehirn Engel de Abreu, Pascale E-print/Working paper (2013) Der „kognitive Vorteil“ der Mehrsprachigkeit besteht darin, dass mehrsprachige Kinder in bestimmten kognitiven Aufgaben, welche die sogenannten „exekutiven Funktionen“ messen, besser sind als Kinder, die ... [more ▼] Der „kognitive Vorteil“ der Mehrsprachigkeit besteht darin, dass mehrsprachige Kinder in bestimmten kognitiven Aufgaben, welche die sogenannten „exekutiven Funktionen“ messen, besser sind als Kinder, die nur eine Sprache sprechen. [less ▲] Detailed reference viewed: 225 (9 UL)Asset Pricing Implications of Macroeconomic Interventions An Application to Climate Policy Mehra, Rajnish E-print/Working paper (2013) Detailed reference viewed: 51 (0 UL)Macroeconomic Foundations of Financial Predictability Mehra, Rajnish ; E-print/Working paper (2013) Detailed reference viewed: 139 (9 UL)Upside down with the strong partial clones Schölzel, Karsten E-print/Working paper (2013) Detailed reference viewed: 33 (5 UL)Cobham's theorem for abstract numeration systems ; Leroy, Julien ; E-print/Working paper (2013) Detailed reference viewed: 22 (0 UL)Asymmetric contests with risky rents Guigou, Jean-Daniel E-print/Working paper (2013) Detailed reference viewed: 54 (4 UL)Rights offerings, trading and regulation : a global perspective Vermaelen, Theo ; ; E-print/Working paper (2013) Detailed reference viewed: 59 (0 UL)Buybacks around the world Vermaelen, Theo ; ; E-print/Working paper (2013) Detailed reference viewed: 61 (1 UL)Declining bargaining power of workers and the rise of early retirement in Europe ; ; et al E-print/Working paper (2013) We offer an alternative explanation for the decline in labor force participation of senior workers. Typically, tax and transfer explanations have been proposed. On the contrary, a model with imperfectly ... [more ▼] We offer an alternative explanation for the decline in labor force participation of senior workers. Typically, tax and transfer explanations have been proposed. On the contrary, a model with imperfectly competitive labor market allows to consider as well the effects of a drop in bargaining power, which would not be possible in a purely neoclassical framework. We find that a decline in the bargaining power of workers, which has taken place in the last four decades, has largely contributed to the rise in inactivity in Europe. However, we need a combination of these two explanations, along with population aging and a fall in the matching efficiency, in order to correctly reproduce the joint evolutions of other labor market variables such as the employment and unemployment rates. [less ▲] Detailed reference viewed: 945 (4 UL)Skewness Risk Premium: Theory and Empirical Evidence Lehnert, Thorsten ; Wolff, Christian ; E-print/Working paper (2013) Detailed reference viewed: 162 (4 UL)Stein’s Overeaction Puzzle: Option Anomaly or Perfectly Rational Behavior Lehnert, Thorsten ; Martelin, Nicolas ; E-print/Working paper (2013) Detailed reference viewed: 75 (5 UL)The Impact of Policy Interventions on Stock Liquidity Lehnert, Thorsten ; E-print/Working paper (2013) Detailed reference viewed: 25 (3 UL)Estimation Risk in Option Pricing Lehnert, Thorsten ; ; E-print/Working paper (2013) Detailed reference viewed: 44 (3 UL)Washington Meets Wall Street: A Closer Examination of the Presidential Cylce Puzzle Kräussl, Roman ; ; et al E-print/Working paper (2013) Detailed reference viewed: 34 (2 UL)Has Europe Been Catching Up? An Industry Level Analysis of Venture Capital Success over 1985-2009* Kräussl, Roman ; E-print/Working paper (2013) Detailed reference viewed: 60 (2 UL)The index of an Eisenstein ideal of multiplicity one Yoo, Hwajong E-print/Working paper (2013) Mazur’s fundamental work on Eisenstein ideals for prime level has a variety of arith- metic applications. In this article, we generalize his work to arbitrary square-free level. We compute the index of an ... [more ▼] Mazur’s fundamental work on Eisenstein ideals for prime level has a variety of arith- metic applications. In this article, we generalize his work to arbitrary square-free level. We compute the index of an Eisenstein ideal and the dimension of the m-torsion of the modular Jacobian vari- ety, where m is an Eisenstein maximal ideal. In many cases, the dimension of the m-torsion is 2, in other words, multiplicity one theorem holds. [less ▲] Detailed reference viewed: 167 (3 UL)From tax evasion to tax planning Bourgain, Arnaud ; Pieretti, Patrice ; Zanaj, Skerdilajda E-print/Working paper (2013) This paper analyzes within a simple model how a removal of bank secrecy can impact tax revenues and banks'profitability, assuming that offshore centers are able to offer sophisticated but legal, tax ... [more ▼] This paper analyzes within a simple model how a removal of bank secrecy can impact tax revenues and banks'profitability, assuming that offshore centers are able to offer sophisticated but legal, tax planning. Two alternative regimes are considered. A first, in which there is strict bank secrecy and a second, where there is international information exchange for tax purposes. In particular, we show that sharing tax information with onshore countries can be a dominant strategy for an OFC if there is enough scope for providing tax planning. Moreover, a partial reduction of tax liabilities can already prompt OFCs to voluntarily exchange relevant tax information. We also discuss the conditions under which the possible removal of bank secrecy may reduce or increase the onshore country's tax revenue. [less ▲] Detailed reference viewed: 278 (109 UL)Modeling default correlation in a US retail loan portfolio Pisa, Magdalena ; Wolff, Christian ; E-print/Working paper (2012) Detailed reference viewed: 67 (1 UL)Measuring the Bid-Ask Spreads: A Note on the Potential Downward Bias of the Thompson-Waller Estimator Otsubo, Yoichi E-print/Working paper (2012) Detailed reference viewed: 72 (3 UL)Vertically Splitting a Firm:Promotion and Demotion in a Team Production Experiment Neugebauer, Tibor ; ; et al E-print/Working paper (2012) Detailed reference viewed: 19 (1 UL)Sentiment Trades and Option Prices Lehnert, Thorsten ; ; E-print/Working paper (2012) Detailed reference viewed: 12 (0 UL)The 2007‐2009 Financial Crisis: Changing Market Dynamics and the Impact of Credit Supply and Aggregate Demand Sensitivity* Grammatikos, Theoharry ; Vermeulen, Robert John Gerard E-print/Working paper (2012) Detailed reference viewed: 111 (0 UL)Lectures on Supergeometry Covolo, Tiffany ; Poncin, Norbert E-print/Working paper (2012) Detailed reference viewed: 428 (129 UL)Fiber bundles and connections Poncin, Norbert E-print/Working paper (2012) Detailed reference viewed: 151 (24 UL)Euro at Risk: The Impact of Member Countries Credit Risk on the Stability of the Common Currency Bekkour, Lamia ; Jin, Xisong ; Lehnert, Thorsten et al E-print/Working paper (2012) Detailed reference viewed: 136 (15 UL)The Governance of Perpetual Financial Intermediaries Van Bommel, Jos ; E-print/Working paper (2012) Detailed reference viewed: 82 (4 UL)Limited Liability, Moral Hazard and Risk Taking – A Safety Net Game Neugebauer, Tibor ; E-print/Working paper (2012) Detailed reference viewed: 23 (1 UL)Market Perceptions of US and European Policy Actions Around the Subprime Crisis Grammatikos, Theoharry ; Lehnert, Thorsten ; Otsubo, Yoichi E-print/Working paper (2012) Detailed reference viewed: 105 (4 UL)Noise Trading and the Cross-Section of Index Option Prices Irek, Fabian ; ; Lehnert, Thorsten et al E-print/Working paper (2012) Detailed reference viewed: 27 (1 UL)Excludability and Contribution: A Laboratory Study in Team Production Neugebauer, Tibor ; ; E-print/Working paper (2012) Detailed reference viewed: 75 (1 UL)Does the GARCH Structural Credit Risk Model Make a Difference? Jin, Xisong ; Lehnert, Thorsten E-print/Working paper (2011) In this study, we empirically investigate and evaluate various approaches to structurally assess credit risk using a panel of European banking groups. We consider not only the standard approaches in the ... [more ▼] In this study, we empirically investigate and evaluate various approaches to structurally assess credit risk using a panel of European banking groups. We consider not only the standard approaches in the literature, but also include models that allow the asset volatility to be stochastic and models that allow for short- and long-term components of default risk. Models are evaluated by comparing their ability to correctly and timely identify changes in risk indicators. Surprisingly, we find that the GARCH structural credit risk model, despite its more sophisticated modeling approach, typically underperforms more basic models. Importantly for macro-prudential policy, the combined Merton/GARCH-MIDAS model performs best and reflects important market events earlier than the other approaches. [less ▲] Detailed reference viewed: 124 (3 UL)The Relative Informational Efficiency of Stocks, Options and Credit Default Swaps Bekkour, Lamia ; Lehnert, Thorsten ; E-print/Working paper (2011) Detailed reference viewed: 64 (1 UL)Transparency and Ending Times of Call Auctions: A Comparison of Euronext and Xetra Van Bommel, Jos ; E-print/Working paper (2011) Detailed reference viewed: 43 (1 UL)Strategic Delegation and Collusion: Do Incentive Schemes Matter? Guigou, Jean-Daniel ; ; E-print/Working paper (2011) Detailed reference viewed: 23 (0 UL)Financial Intermediation in an Overlapping Generations Model with Transaction Costs Van Bommel, Jos ; ; E-print/Working paper (2011) Detailed reference viewed: 95 (2 UL)Public Good and Private Good Valuation for Waiting, Time Reduction: A Laboratory Study Neugebauer, Tibor ; E-print/Working paper (2011) Detailed reference viewed: 57 (1 UL)Cultural Values, CEO Risk Aversion and Corporate Takeovers Lehnert, Thorsten ; ; et al E-print/Working paper (2011) Detailed reference viewed: 72 (2 UL)Large Portfolio Risk Management and Optimal Portfolio Allocation with Dynamic Copulas Jin, Xisong ; Lehnert, Thorsten E-print/Working paper (2011) Detailed reference viewed: 77 (2 UL)Corporate Governance and Financial Development: A Study of the French Case Guigou, Jean-Daniel ; ; et al E-print/Working paper (2011) Detailed reference viewed: 77 (2 UL)Lectures on Algebraic Operads ; Poncin, Norbert E-print/Working paper (2011) Detailed reference viewed: 148 (18 UL)The Relative Informational Efficiency of Stocks, Options and Credit Default Swaps Bekkour, Lamia ; Lehnert, Thorsten ; E-print/Working paper (2011) Detailed reference viewed: 65 (2 UL)Using Monte Carlo to Price Continuously Monitored Barrier Options on Discontinuously Traded Underlyings Van Bommel, Jos E-print/Working paper (2011) Detailed reference viewed: 52 (2 UL)Luxemburger Auswanderer und ihre Nachfahren in den USA Eine Sekundärauswertung der American Community Survey Fehlen, Fernand E-print/Working paper (2010) Detailed reference viewed: 91 (8 UL)Georges-Louis Leclerc de Buffon’s ‘Essays on Moral Arithmetic Neugebauer, Tibor ; ; E-print/Working paper (2010) Detailed reference viewed: 118 (1 UL)Who makes the pie bigger? An experimental study on co-opetition Neugebauer, Tibor ; ; E-print/Working paper (2010) Detailed reference viewed: 83 (1 UL)Transmission of the Financial and Sovereign Debt Crises to the EMU: Stock Prices, CDS Spreads and Exchange Rates Grammatikos, Theoharry ; Vermeulen, Robert John Gerard E-print/Working paper (2010) Detailed reference viewed: 73 (2 UL)Moral Impossibility in the Petersburg Paradox : A Literature Survey and Experimental Evidence Neugebauer, Tibor E-print/Working paper (2010) Detailed reference viewed: 52 (1 UL)Contingent Capital: The Case for COERCs Wolff, Christian ; Vermaelen, Theo ; E-print/Working paper (2010) Detailed reference viewed: 19 (0 UL)Modeling structural changes in the volatility process Lehnert, Thorsten ; ; E-print/Working paper (2010) Detailed reference viewed: 55 (1 UL)Limited Liability, Moral Hazard and Risk Taking - A Safety Net Game Experiment Neugebauer, Tibor ; E-print/Working paper (2010) Detailed reference viewed: 59 (4 UL)Théorie des représentations du groupe symétrique ; Poncin, Norbert E-print/Working paper (2009) Detailed reference viewed: 61 (4 UL)A Cumulative Prospect Theory Approach to Option Pricing Lehnert, Thorsten ; Wolff, Christian ; E-print/Working paper (2009) Detailed reference viewed: 138 (0 UL)Dispersion of Beliefs in the Foreign Exchange Market Wolff, Christian ; ; et al E-print/Working paper (2009) Detailed reference viewed: 11 (0 UL)Behavioral Heterogeneity in the Option Market Lehnert, Thorsten ; ; E-print/Working paper (2009) Detailed reference viewed: 59 (0 UL)Time-Variation in Term Permia: International Survey-Based Evidence Wolff, Christian ; ; E-print/Working paper (2009) Detailed reference viewed: 22 (0 UL)Law, corporate governance and financial system: Econometric analysis of French case Guigou, Jean-Daniel ; ; Blazy, Régis et al E-print/Working paper (2008) Detailed reference viewed: 35 (0 UL)Loss Functions in Option Valuation: A Framework for Selection Lehnert, Thorsten ; Wolff, Christian ; E-print/Working paper (2008) Detailed reference viewed: 72 (0 UL)An Experimental Analysis of Optimal Renewable Resource Management:The Fishery Neugebauer, Tibor ; ; E-print/Working paper (2008) Detailed reference viewed: 59 (1 UL)Are Capital Controls in the Foreign Exchange Market Effective? Wolff, Christian ; ; E-print/Working paper (2008) Detailed reference viewed: 56 (0 UL)On maximal independent sets in circulant digraphs Bisdorff, Raymond E-print/Working paper (2007) In this research note we introduce St-Nicolas graphs, i.e. circulant digraphs showing exactly n maximal independent sets, isomorph under the digraph’s automorphisms group. This class of digraphs represent ... [more ▼] In this research note we introduce St-Nicolas graphs, i.e. circulant digraphs showing exactly n maximal independent sets, isomorph under the digraph’s automorphisms group. This class of digraphs represent a generalisation of Andrásfai graphs with interesting links to finite group theory. [less ▲] Detailed reference viewed: 20 (1 UL)Relative Performance Evaluation, Risk Aversion and Entry Guigou, Jean-Daniel ; ; Piaser, Gwenaël E-print/Working paper (2007) Detailed reference viewed: 20 (0 UL)Financial versus Social Efficiency of Corporate Bankruptcy Law: the French Dilemma ? Guigou, Jean-Daniel ; BLAZY, Régis ; et al E-print/Working paper (2007) Detailed reference viewed: 68 (0 UL)Bid and price effects of increased competition in the first-price auction: experimental evidence Neugebauer, Tibor E-print/Working paper (2007) Detailed reference viewed: 31 (1 UL)Evaluation des performances relatives, risque et entrée Guigou, Jean-Daniel ; E-print/Working paper (2006) Detailed reference viewed: 24 (0 UL)Impact de l’attrait des places bancaires sur les taux d’intérêt créditeurs : Un modèle de formation des taux créditeurs estimé sur données en panel de banques européennes Bourgain, Arnaud ; Pieretti, Patrice ; E-print/Working paper (2001) This article evaluates the impact of banking centers' attractiveness on deposit interest rates. Using balance-sheet data from a set of 135 banks, the authors test an intermediation model of deposit rate ... [more ▼] This article evaluates the impact of banking centers' attractiveness on deposit interest rates. Using balance-sheet data from a set of 135 banks, the authors test an intermediation model of deposit rate determination. In particular, the investigation shows a significant impact of « confidentiality » on deposit rates, thus confirming the importance of qualitative variables favouring local differentiation and clustering of banking activities. [less ▲] Detailed reference viewed: 65 (0 UL)Effets de complémentarité externes et incidence sur la productivité : le cas de l'industrie manufacturière luxembourgeoise Bourgain, Arnaud ; Pieretti, Patrice E-print/Working paper (2001) This article seeks to measure knowledge spillovers between nearby industries. This represents one of types of externality identified in the studies of industry location. A spillover indicator is suggested ... [more ▼] This article seeks to measure knowledge spillovers between nearby industries. This represents one of types of externality identified in the studies of industry location. A spillover indicator is suggested which can explain increasing returns at the aggregate level. It is shown that this indicator is positively related to industry diversity. As applied to data from Luxembourg’s manufacturing industry, this indicator suggests that labor productivity is increasing in industry diversity. [less ▲] Detailed reference viewed: 59 (0 UL)Hinweis auf das Projekt : Effizienz des Frühunterrichts: begleitende Forschung im Rahmen der Fremdsprachenreformen“, esquisse de l’orientation de la recherche conduite au sein du projet d’étude sur l’introduction de l’enseignement précoce du français dans les écoles primaires de la Sarre Ehrhart, Sabine ; E-print/Working paper (2001) Detailed reference viewed: 47 (2 UL)Analyse de l’évolution de la productivité totale des facteurs dans l’industrie luxembourgeoise Bourgain, Arnaud ; Pieretti, Patrice E-print/Working paper (1999) Detailed reference viewed: 52 (0 UL)On linear decompositions of L-valued simple graphs Bisdorff, Raymond E-print/Working paper (1996) In this report we will present a linear decomposition of a given L- valued binary relation into a set of sub-relations of kernel-dimension one. We will apply this theoretical result to the design of a ... [more ▼] In this report we will present a linear decomposition of a given L- valued binary relation into a set of sub-relations of kernel-dimension one. We will apply this theoretical result to the design of a faster algorithm for computing L-valued kernels on general L-valued simple graphs. [less ▲] Detailed reference viewed: 12 (0 UL)Le français langue seconde dans les écoles maternelles et primaires de la République de Vanuatu (Pacifique Sud), Bilan d’une année d’étude dans le cadre de la « bourse d‘excellence postdoctorale Aupelf-Uref » Ehrhart, Sabine E-print/Working paper (1995) Detailed reference viewed: 40 (2 UL)Quelques réflexions concernant la genèse du tayo en Nouvelle-Calédonie et discussion des éventuels apports venant de l’extérieur, notamment du créole réunionnais, Conférence donnée à l'Université de Münster, 1991 Ehrhart, Sabine E-print/Working paper (1994) Detailed reference viewed: 93 (0 UL)Kummer theory for number fields via entanglement groups Perucca, Antonella ; Sgobba, Pietro ; Tronto, Sebastiano E-print/Working paper (n.d.) Let $K$ be a number field, and let $G$ be a finitely generated and torsion-free subgroup of $K^\times$. We are interested in computing the degree of the cyclotomic-Kummer extension $K(\sqrt[n]{G})$ over ... [more ▼] Let $K$ be a number field, and let $G$ be a finitely generated and torsion-free subgroup of $K^\times$. We are interested in computing the degree of the cyclotomic-Kummer extension $K(\sqrt[n]{G})$ over $K$, where $\sqrt[n]{G}$ consists of all $n$-th roots of the elements of $G$. We develop the theory of entanglements introduced by Lenstra, and apply it to compute the above degrees. [less ▲] Detailed reference viewed: 78 (3 UL)Weakening the tight coupling between geometry and simulation in isogeometric analysis: from sub- and super- geometric analysis to Geometry Independent Field approximaTion (GIFT) ; ; Tomar, Satyendra et al E-print/Working paper (n.d.) This paper presents an approach to generalize the concept of isogeometric analysis (IGA) by allowing different spaces for parameterization of the computational domain and for approximation of the solution ... [more ▼] This paper presents an approach to generalize the concept of isogeometric analysis (IGA) by allowing different spaces for parameterization of the computational domain and for approximation of the solution field. The method inherits the main advantage of isogeometric analysis, i.e. preserves the original, exact CAD geometry (for example, given by NURBS), but allows pairing it with an approximation space which is more suitable/flexible for analysis, for example, T-splines, LR-splines, (truncated) hierarchical B-splines, and PHT-splines. This generalization offers the advantage of adaptive local refinement without the need to re-parameterize the domain, and therefore without weakening the link with the CAD model. We demonstrate the use of the method with different choices of the geometry and field splines, and show that, despite the failure of the standard patch test, the optimum convergence rate is achieved for non-nested spaces. [less ▲] Detailed reference viewed: 255 (13 UL)Reductions of points on algebraic groups II ; Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 8 (1 UL)Kummer extensions of number fields (the case of rank 2) II Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 14 (1 UL)The problem of detecting linear dependence Perucca, Antonella E-print/Working paper (n.d.) Detailed reference viewed: 58 (1 UL)The degree of Kummer extensions of number fields Perucca, Antonella ; Sgobba, Pietro ; Tronto, Sebastiano E-print/Working paper (n.d.) Detailed reference viewed: 65 (4 UL)Explicit Kummer Theory for the rational numbers Perucca, Antonella ; Sgobba, Pietro ; Tronto, Sebastiano E-print/Working paper (n.d.) Detailed reference viewed: 138 (21 UL)Kummer theory for one-dimensional tori Perucca, Antonella ; E-print/Working paper (n.d.) Detailed reference viewed: 37 (5 UL)Explicit Kummer theory for quadratic fields ; Perucca, Antonella ; Sgobba, Pietro et al E-print/Working paper (n.d.) Let K be a number field, and let \alpha \in K be an algebraic number which is neither 0 nor a root of unity. The ratio between n and the Kummer degree [K(\zeta_m,\sqrt[n]{\alpha}):K(\zeta_m)], where n ... [more ▼] Let K be a number field, and let \alpha \in K be an algebraic number which is neither 0 nor a root of unity. The ratio between n and the Kummer degree [K(\zeta_m,\sqrt[n]{\alpha}):K(\zeta_m)], where n divides m, is known to be bounded independently of n and m. For some families of quadratic number fields we describe an explicit algorithm that provides formulas for all those Kummer degrees. In particular, for the given fields we are able to give explicit expressions for the Kummer extensions contained in a cyclotomic extension. [less ▲] Detailed reference viewed: 45 (5 UL)A new one point quadrature rule over arbitrary star convex polygon/polyhedron ; ; et al E-print/Working paper (n.d.) The Linear Smoothing (LS) scheme \cite{francisa.ortiz-bernardin2017} ameliorates linear and quadratic approximations over convex polytopes by employing a three-point integration scheme. In this work, we ... [more ▼] The Linear Smoothing (LS) scheme \cite{francisa.ortiz-bernardin2017} ameliorates linear and quadratic approximations over convex polytopes by employing a three-point integration scheme. In this work, we propose a linearly consistent one point integration scheme which possesses the properties of the LS scheme with three integration points but requires one third of the integration computational time. The essence of the proposed technique is to approximate the strain by the smoothed nodal derivatives that are determined by the discrete form of the divergence theorem. This is done by the Taylor's expansion of the weak form which facilitates the evaluation of the smoothed nodal derivatives acting as stabilization terms. The smoothed nodal derivatives are evaluated only at the centroid of each integration cell. These integration cells are the simplex subcells (triangle/tetrahedron in two and three dimensions) obtained by subdividing the polytope. The salient feature of the proposed technique is that it requires only $n$ integrations for an $n-$ sided polytope as opposed to $3n$ in~\cite{francisa.ortiz-bernardin2017} and $13n$ integration points in the conventional approach. The convergence properties, the accuracy, and the efficacy of the LS with one point integration scheme are discussed by solving few benchmark problems in elastostatics. [less ▲] Detailed reference viewed: 55 (3 UL)Linear smoothed polygonal and polyhedral finite elements ; ; Bordas, Stéphane et al E-print/Working paper (n.d.) It was observed in [1, 2] that the strain smoothing technique over higher order elements and arbitrary polytopes yields less accurate solutions than other techniques such as the conventional polygonal ... [more ▼] It was observed in [1, 2] that the strain smoothing technique over higher order elements and arbitrary polytopes yields less accurate solutions than other techniques such as the conventional polygonal finite element method. In this work, we propose a linear strain smoothing scheme that improves the accuracy of linear and quadratic approximations over convex polytopes. The main idea is to subdivide the polytope into simplicial subcells and use a linear smoothing function in each subcell to compute the strain. This new strain is then used in the computation of the stiffness matrix. The convergence properties and accuracy of the proposed scheme are discussed by solving few benchmark problems. Numerical results show that the proposed linear strain smoothing scheme makes the approximation based on polytopes to deliver improved accuracy and pass the patch test to machine precision. [less ▲] Detailed reference viewed: 426 (10 UL)Linear smoothed extended finite element method ; ; et al E-print/Working paper (n.d.) The extended finite element method (XFEM) was introduced in 1999 to treat problems involving discontinuities with no or minimal remeshing through appropriate enrichment functions. This enables elements to ... [more ▼] The extended finite element method (XFEM) was introduced in 1999 to treat problems involving discontinuities with no or minimal remeshing through appropriate enrichment functions. This enables elements to be split by a discontinuity, strong or weak and hence requires the integration of discontinuous functions or functions with discontinuous derivatives over elementary volumes. Moreover, in the case of open surfaces and singularities, special, usually non-polynomial functions must also be integrated.A variety of approaches have been proposed to facilitate these special types of numerical integration, which have been shown to have a large impact on the accuracy and convergence of the numerical solution. The smoothed extended finite element method (SmXFEM) [1], for example, makes numerical integration elegant and simple by transforming volume integrals into surface integrals. However, it was reported in [1, 2] that the strain smoothing is inaccurate when non-polynomial functions are in the basis. This is due to the constant smoothing function used over the smoothing domains which destroys the effect of the singularity. In this paper, we investigate the benefits of a recently developed Linear smoothing procedure [3] which provides better approximation to higher order polynomial fields in the basis. Some benchmark problems in the context of linear elastic fracture mechanics (LEFM) are solved to compare the standard XFEM, the constant-smoothed XFEM (Sm-XFEM) and the linear-smoothed XFEM (LSm-XFEM). We observe that the convergence rates of all three methods are the same. The stress intensity factors (SIFs) computed through the proposed LSm-XFEM are however more accurate than that obtained through Sm-XFEM. To conclude, compared to the conventional XFEM, the same order of accuracy is achieved at a relatively low computational effort. [less ▲] Detailed reference viewed: 99 (3 UL) |
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