In this paper, we use Ditzian-Totik modulus to study the pointwise approximation for the linear combinations of Szdász-type operators, and obtain the direct and converse theorem and the characterization of the po...In this paper, we use Ditzian-Totik modulus to study the pointwise approximation for the linear combinations of Szdász-type operators, and obtain the direct and converse theorem and the characterization of the pointwise approximation for the linear combinations of Szdász-type operators.展开更多
文摘In this paper, we use Ditzian-Totik modulus to study the pointwise approximation for the linear combinations of Szdász-type operators, and obtain the direct and converse theorem and the characterization of the pointwise approximation for the linear combinations of Szdász-type operators.