87,834 research outputs found
The cohomology of the braid group and of with coefficients in a geometric representation
No full textThis article is a short version of a paper which addresses the cohomology of the third braid group and of with coefficients in geometric representations.We give precise statements of the results, some tools and some proofs, avoiding very technical computations here
Towards the simulation of cavitating flows in inducers through a homogeneous barotropic flow model
No full textThe Salvetti complex and the little cubes
No full textFor a real central arrangement A, Salvetti introduced a construction of a finite complex Sal(A) which is homotopy equivalent to the complement of the complexified arrangement in [Sal87]. For the braid arrangement A(k-1), the Salvetti complex Sal(A(k-1)) serves as a good combinatorial model for the homotopy type of the configuration space F(C, k) of k points in C, which is homotopy equivalent to the space C-2(k) of k little 2-cubes. Motivated by the importance of little cubes in homotopy theory, especially in the study of iterated loop spaces, we study how the combinatorial structure of the Salvetti complexes of the braid arrangements is related to homotopy-theoretic properties of iterated loop spaces. We prove that the skeletal filtrations on the Salvetti complexes of the braid arrangements give rise to the cobar-type Eilenberg-Moore spectral sequence converging to the homology of Omega(2)Sigma X-2. We also construct a new spectral sequence that computes the homology of Omega(l)Sigma X-l for l > 2 by using a higher order analogue of the Salvetti complex. The E-1-term of the spectral sequence is described in terms of the homology of X. The spectral sequence is different from known spectral sequences that compute the homology of iterated loop spaces, such as the Eilenberg-Moore spectral sequence and the spectral sequence studied by Ahearn and Kuhn in [AK02]
The Salvetti complex and the little cubes
No full textFor a real central arrangement A, Salvetti introduced a construction of a finite complex Sal(A) which is homotopy equivalent to the complement of the complexified arrangement in [Sal87]. For the braid arrangement A(k-1), the Salvetti complex Sal(A(k-1)) serves as a good combinatorial model for the homotopy type of the configuration space F(C, k) of k points in C, which is homotopy equivalent to the space C-2(k) of k little 2-cubes. Motivated by the importance of little cubes in homotopy theory, especially in the study of iterated loop spaces, we study how the combinatorial structure of the Salvetti complexes of the braid arrangements is related to homotopy-theoretic properties of iterated loop spaces. We prove that the skeletal filtrations on the Salvetti complexes of the braid arrangements give rise to the cobar-type Eilenberg-Moore spectral sequence converging to the homology of Omega(2)Sigma X-2. We also construct a new spectral sequence that computes the homology of Omega(l)Sigma X-l for l > 2 by using a higher order analogue of the Salvetti complex. The E-1-term of the spectral sequence is described in terms of the homology of X. The spectral sequence is different from known spectral sequences that compute the homology of iterated loop spaces, such as the Eilenberg-Moore spectral sequence and the spectral sequence studied by Ahearn and Kuhn in [AK02].ArticleJOURNAL OF THE EUROPEAN MATHEMATICAL SOCIETY. 14(3):801-840 (2012)journal articl
The effect of the numerical scheme on the subgrid scale term in large-eddy simulation
No full textA priori tests are performed to study the effect of the filter on the subgrid scale term in large-eddy simulation. Several filters, corresponding to finite-difference schemes of different order of accuracy, are applied to direct numerical simulation data. In particular, the effect of the filter on the importance of the Leonard term and on its correlation with the subgrid scale stress is investigated to evaluate, for different numerical schemes, the capabilities of subgrid scale models accounting for this term, such as scale-similarity or mixed models
Analisi, Rilievi e Schedature dei Valori Cromatici del Centro Antico di Albenga. Il progetto di conoscenza e le fasi operative.
No full textLa presente pubblicazione documenta un’esperienza di “Progetto Colore” che, al di là degli aspetti teorici e
metodologici, già assodati, si è rivolta a cercare di definire, per risolvere, una delle problematiche ancora
insolute: ovvero, la trasmissione e la gestione dei dati di questo progetto, in cui sono definite in dettaglio le
linee guida, sia su supporto digitale che cartaceo, e di renderle fruibili al massimo della chiarezza, per
migliorare sia la gestione da parte dei tecnici comunali, sia il rapporto con i professionisti
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