Nous obtenons pour certains revêtements modérés de surfaces arithmétiques des expressions des caractéristiques d’Euler équivariantes du faisceau canonique et de sa racine carrée qui font apparaître une forme quadratique décrite en terme de nombres d’intersection. Ces formules se prêtent au calcul. Elles nous permettent notamment de donner des exemples où ces caractéristiques ainsi que celle du faisceau structural sont deux à deux distinctes et non triviales. Nos résultats s’obtiennent par l’utilisation du théorème de Riemann-Roch local et par un calcul de résolvantes.
For certain tame abelian covers of arithmetic surfaces we obtain formulas, involving a quadratic form derived from intersection numbers, for the equivariant Euler characteristics of both the canonical sheaf and also its square root. These formulas allow us to carry out explicit calculations; in particular, we are able to exhibit examples where these two Euler characteristics and that of the structure sheaf are all different and non-trivial. Our results are obtained by using resolvent techniques together with the local Riemann-Roch Theorem.
Keywords: Euler characteristic, resolvent, intersection numbers.
Mot clés : caratéristique d’Euler, résolvante, nombre d’intersection.
Cassou-Noguès, Ph. 1 ; Taylor, M.J. 2
@article{AIF_2012__62_6_2315_0, author = {Cassou-Nogu\`es, Ph. and Taylor, M.J.}, title = {Equivariant {Euler} characteristics and sheaf resolvents}, journal = {Annales de l'Institut Fourier}, pages = {2315--2345}, publisher = {Association des Annales de l{\textquoteright}institut Fourier}, volume = {62}, number = {6}, year = {2012}, doi = {10.5802/aif.2750}, mrnumber = {3060759}, language = {en}, url = {https://aif.centre-mersenne.org/articles/10.5802/aif.2750/} }
TY - JOUR AU - Cassou-Noguès, Ph. AU - Taylor, M.J. TI - Equivariant Euler characteristics and sheaf resolvents JO - Annales de l'Institut Fourier PY - 2012 SP - 2315 EP - 2345 VL - 62 IS - 6 PB - Association des Annales de l’institut Fourier UR - https://aif.centre-mersenne.org/articles/10.5802/aif.2750/ DO - 10.5802/aif.2750 LA - en ID - AIF_2012__62_6_2315_0 ER -
%0 Journal Article %A Cassou-Noguès, Ph. %A Taylor, M.J. %T Equivariant Euler characteristics and sheaf resolvents %J Annales de l'Institut Fourier %D 2012 %P 2315-2345 %V 62 %N 6 %I Association des Annales de l’institut Fourier %U https://aif.centre-mersenne.org/articles/10.5802/aif.2750/ %R 10.5802/aif.2750 %G en %F AIF_2012__62_6_2315_0
Cassou-Noguès, Ph.; Taylor, M.J. Equivariant Euler characteristics and sheaf resolvents. Annales de l'Institut Fourier, Tome 62 (2012) no. 6, pp. 2315-2345. doi : 10.5802/aif.2750. https://aif.centre-mersenne.org/articles/10.5802/aif.2750/
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