On the middle convolution of local systems . With an Appendix
نویسنده
چکیده
We study the middle convolution of local systems in the setting of singular and étale cohomology. We give a motivic interpretation of the middle convolution in the étale case and prove an independence-of-`-result which yields a description of the determinant. We employ these methods to realize special linear groups regularly as Galois groups over Q(t). In an appendix to this article, written jointly with S. Reiter, we prove the existence of a new motivic local system whose monodromy is dense in the exceptional simple group of type G2.
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