Weyl type theorems of 2×2 upper triangular operator matrices

Let MC=(AC0B) be an upper triangular operator matrix on the Hilbert space H⊕H, where H is a Hilbert space. In this paper, necessary and sufficient conditions for σ⁎(MC)=σ⁎(A)∪σ⁎(B) are obtained, where σ⁎ is the essential spectrum, the Weyl spectrum, the Browder spectrum, the essential approximate point spectrum and the Browder essential approximate point spectrum. For MC, we further investigate the relationship among Weyl type theorems such as Weyl's, a-Weyl's, Browder's and a-Browder's theorems.