Orateur(s)  Ulrich THIEL  Kaiserslautern,

Titre  Decomposition morphisms are generically trivial 
Date  05/06/2014 
Horaire  10:30 à 11:30 

Diffusion  
Résume  In my talk I will address a natural geometric question emerging when trying to compare the specialization $A(0)=A^K$ of a finitedimensional algebra over a normal noetherian ring $R$ with quotient field K in the generic point $(0)$ of $Spec(R)$ to an arbitrary specialization $A(P)$ in a prime ideal $P$ of $R$. I will show that in case $A(P)$ splits for all $P$, the Grothendieck groups of $A^K$ and $A(P)$ are essentially the same on an open subset of $Spec(R)$, where the connection between the Grothendieck groups is set up by decomposition morphisms in the sense of GeckRouquier. This result is a nice tool for studying algebras involving parameters like Hecke algebras and Cherednik algebras. The proof uses both algebraic and topological arguments. 
Salle  11 rue Pierre et Marie Curie  75005 Paris 
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