The Yoneda algebra of a K₂ algebra need not be another K₂ algebra

الأصل · EN

The Yoneda algebra of a Koszul algebra or a D-Koszul algebra is Koszul. K₂ algebras are a natural generalization of Koszul algebras, and one would hope that the Yoneda algebra of a K₂ algebra would be another K₂ algebra. We show that this is not necessarily the case by constructing a monomial K₂ algebra for which the corresponding Yoneda algebra is not K₂.