Clifford deformations of Koszul Frobenius algebras and noncommutative quadrics


Abstract in English

Let $E$ be a Koszul Frobenius algebra. A Clifford deformation of $E$ is a finite dimensional $mathbb Z_2$-graded algebra $E(theta)$, which corresponds to a noncommutative quadric hypersurface $E^!/(z)$, for some central regular element $zin E^!_2$. It turns out that the bounded derived category $D^b(text{gr}_{mathbb Z_2}E(theta))$ is equivalent to the stable category of the maximal Cohen-Macaulay modules over $E^!/(z)$ provided that $E^!$ is noetherian. As a consequence, $E^!/(z)$ is a noncommutative isolated singularity if and only if the corresponding Clifford deformation $E(theta)$ is a semisimple $mathbb Z_2$-graded algebra. The preceding equivalence of triangulated categories also indicates that Clifford deformations of trivial extensions of a Koszul Frobenius algebra are related to the Kn{o}rrer Periodicity Theorem for quadric hypersurfaces. As an application, we recover Kn{o}rrer Periodicity Theorem without using of matrix factorizations.

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