Ji-Wei He

On the Yoneda Ext-Algebras of Semiperfect Algebras

It is proved that the Yoneda Ext-algebras of Morita equivalent semiperfect algebras are graded equivalent. The Yoneda Ext-algebras of noetherian semiperfect algebras are studied in detail. Let A be a noetherian semiperfect algebra with Jacobson radical J. We construct a right ideal

Derived H-module endomorphism rings

\overline{E}(A)

Graded 3-Calabi-Yau algebras as Ore extensions of 2-Calabi-Yau algebras

of the Yoneda algebra

DUALIZING COMPLEXES OF NOETHERIAN COMPLETE ALGEBRAS VIA COALGEBRAS

E(A)={\rm Ext}^*_A(A/J,A/J)

Calabi–Yau Coalgebras

, which plays an important role in the discussion of the structure of E(A). An extra grading is introduced to

Deformations of Quadratic Algebras with Antisymmetric Relations

\overline{E}(A)

Higher Koszul algebras and A-infinity algebras

, by which we give a description of the right ideal of E(A) generated by

Cocommutative Calabi–Yau Hopf algebras and deformations

{\rm Ext}^1_A(A/J,A/J)

Koszul differential graded algebras and BGG correspondence

, and we give a necessary and sufficient condition for a notherian semiperfect algebra to be higher quasi-Koszul. Finally, it is shown that the quasi-Koszulity of a noetherian semiperfect algebra is a Morita invariant.

Skew polynomial algebras with coefficients in Koszul Artin–Schelter regular algebras

Let