A McKay Correspondence for Reflection Groups

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Datum
2018-07-02MFO Scientific Program
OWLF 2017Serie
Oberwolfach Preprints;2018,14Autor
Buchweitz, Ragnar-Olaf
Faber, Eleonore
Ingalls, Colin
Metadata
Zur LanganzeigeOWP-2018-14
Zusammenfassung
We construct a noncommutative desingularization of the discriminant of a finite reflection group $G$ as a quotient of the skew group ring $A=S*G$. If $G$ is generated by order two reflections, then this quotient identifies with the endomorphism ring of the reflection arrangement $\mathcal{A}(G)$ viewed as a module over the coordinate ring $S^G/(\Delta)$ of the discriminant of $G$. This yields, in particular, a correspondence between the nontrivial irreducible representations of $G$ to certain maximal Cohen--Macaulay modules over the coordinate ring $S^G/(\Delta)$. These maximal Cohen--Macaulay modules are precisely the nonisomorphic direct summands of the coordinate ring of the reflection arrangement $\mathcal{A} (G)$ viewed as a module over $S^G/(\Delta)$. We identify some of the corresponding matrix factorizations, namely the so-called logarithmic co-residues of the discriminant.