Let x0 be a fixed real number, and let f be a regular complex function in the half-plane ℜz>x0 for which there exists a nonnegative function F∈L1(−∞,+∞) satisfying ∣f(α+iβ)∣≤F(β) whenever α>x0 , −∞<β<+∞. Prove that ∫α−i∞α+i∞f(z)dz=0.
L. Czach functionintegrationcomplex analysiscomplex analysis unsolved