 Let "D" be an open set containing σ("T").Suppose Γ = {γ"i"} and Ω = {ω"j"} are two (finite) collections of Jordan curves satisfying the assumption given for the functional calculus.We wish to show

Let Ω′ be obtained from Ω by reversing the orientation of each ω"j", then

Consider the union of the two collections Γ ∪ Ω′.