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Consortium of Swiss Academic Libraries

Plünnecke inequalities for countable abelian groups

Björklund, Michael ; Fish, Alexander

In: Journal für die reine und angewandte Mathematik, 2017, vol. 2017, no. 730, p. 199-224

Università della Svizzera italiana

Multilevel solution strategies for unfitted finite element methods

Kothari, Hardik ; Krause, Rolf (Dir.)

Thèse de doctorat : Università della Svizzera italiana, 2020 ; 2020INFO009.

In the unfitted finite element methods, traditionally we can use Nitsche's method or the method of Lagrange multipliers to enforce the boundary/interface conditions. In this work, we present tailored multilevel methods for solving the problems stemming from either of these discretizations. Generally, multigrid methods require a hierarchy of finite element (FE) spaces which can be created...

Consortium of Swiss Academic Libraries

A survey of uncertainty principles and some signal processing applications

Ricaud, Benjamin ; Torrésani, Bruno

In: Advances in Computational Mathematics, 2014, vol. 40, no. 3, p. 629-650

Université de Fribourg

Metric currents and the Poincaré inequality

Fässler, Katrin ; Orponen, Tuomas

In: Calculus of Variations and Partial Differential Equations, 2019, vol. 58, no. 2, p. 69

We show that a complete doubling metric space (X,d,μ) supports a weak 1-Poincaré inequality if and only if it admits a pencil of curves (PC) joining any pair of points s,t∈X . This notion was introduced by S. Semmes in the 90’s, and has been previously known to be a sufficient condition for the weak 1-Poincaré inequality. Our argument passes through the intermediate notion of a...

Université de Fribourg

Testing exclusion restrictions and additive separability in sample selection models

Huber, Martin ; Mellace, Giovanni

In: Empirical economics, 2014, vol. 47, no. 1, p. 75-92

Standard sample selection models with non-randomly censored outcomes assume (i) an exclusion restriction (i.e., a variable affecting selection, but not the outcome) and (ii) additive separability of the errors in the selection process. This paper proposes tests for the joint satisfaction of these assumptions by applying the approach of Huber and Mellace (Testing instrument validity for LATE...