Abstract
Let H be a quasi-Hopf algehra and A a quasi-associative algebra in H H YD. Let X and Y be subalgebras of A in H H YD that are quasi H-commutative and are such that m = mx + my, where m, mx = m|x and my = m|y denotes the multiplication of A, X und Y respectively. If the braiding CA, A is Symmetric on A, then we obtain the morphism identity: mA((m − mCx,y) ⊗ (m − mCx,y)) = 0. As an application of our theory, we get an analogue of the classical Kegel's theorem for quasi-associative algebra in Corollary 4.13, generalizing the one in Wang (2002).