Drazin spectrum of operator matrices on the Banach space

When A∈B(X) and B∈B(Y) are given, we denote by MC the operator acting on the Banach space X⊕Y of the form . In this paper, it is concluded and proved that for a given pair (A,B) of operators, σD(A)∪σD(B)=σD(MC)∪W holds for every C∈B(Y,X), where W is the union of certain holes in σD(MC), which happen to be subsets of σD(A)∩σD(B). Moreover, the set ⋂C∈B(Y,X)σD(MC) is investigated and an example for it is considered.