Nous donnons une estimation polynomiale pour la fonction de densité spectrale d’une matrice sur l’algèbre complexe du groupe . Ce résultat donne une borne inférieure explicite à l’invariant de Novikov-Shubin associé à la matrice, montrant en particulier que l’invariant de Novikov-Shubin est strictement positif.
We give a polynomial bound on the spectral density function of a matrix over the complex group ring of . It yields an explicit lower bound on the Novikov-Shubin invariant associated to this matrix showing in particular that the Novikov-Shubin invariant is larger than zero.
Keywords: spectral density function, Novikov-Shubin invariants
Mot clés : Invariants de Novikov-Shubin, fonction de densité spectrale
@article{AMBP_2015__22_1_73_0, author = {L\"uck, Wolfgang}, title = {Estimates for spectral density functions of matrices over $\mathbb{C}[\mathbb{Z}^d]$}, journal = {Annales math\'ematiques Blaise Pascal}, pages = {73--88}, publisher = {Annales math\'ematiques Blaise Pascal}, volume = {22}, number = {1}, year = {2015}, doi = {10.5802/ambp.346}, language = {en}, url = {http://www.numdam.org/articles/10.5802/ambp.346/} }
TY - JOUR AU - Lück, Wolfgang TI - Estimates for spectral density functions of matrices over $\mathbb{C}[\mathbb{Z}^d]$ JO - Annales mathématiques Blaise Pascal PY - 2015 SP - 73 EP - 88 VL - 22 IS - 1 PB - Annales mathématiques Blaise Pascal UR - http://www.numdam.org/articles/10.5802/ambp.346/ DO - 10.5802/ambp.346 LA - en ID - AMBP_2015__22_1_73_0 ER -
%0 Journal Article %A Lück, Wolfgang %T Estimates for spectral density functions of matrices over $\mathbb{C}[\mathbb{Z}^d]$ %J Annales mathématiques Blaise Pascal %D 2015 %P 73-88 %V 22 %N 1 %I Annales mathématiques Blaise Pascal %U http://www.numdam.org/articles/10.5802/ambp.346/ %R 10.5802/ambp.346 %G en %F AMBP_2015__22_1_73_0
Lück, Wolfgang. Estimates for spectral density functions of matrices over $\mathbb{C}[\mathbb{Z}^d]$. Annales mathématiques Blaise Pascal, Tome 22 (2015) no. 1, pp. 73-88. doi : 10.5802/ambp.346. http://www.numdam.org/articles/10.5802/ambp.346/
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