Suppose M is a left R-module. If the left annihilator of any element of End_R(M) is a direct summand of M, then M is called left Richart;
Suppose M is a left R-module. If the left annihilator of any element of End_R(M) is a direct summand of M, then M is called left Richart;
设M是左R-模,若End_R(M)中任意元φ在M中的左零化子是M的直和项,则称M是左Richart模;