Ring extension problem, Shukla cohomology and Ann-category theory

Nguyen Tien Quang, Nguyen Thu Thuy

Every ring extension of $A$ by $R$ induces a pair of group homomorphisms ${\mathcal{L}}^{\ast }:R\to En{d}_{\mathbb{Z}}(A)/L(A);{\mathcal{R}}^{\ast }:R\to En{d}_{\mathbb{Z}}(A)/R(A),$ preserving multiplication, satis…