KnowraJordan's lemmaLinked fromLinked fromThe 5 pages that link to Jordan's lemma, each with the reason it gives.All 5Related 4Compared with 1Complex analysisRelated: It helps evaluate real integrals using the residue theorem.Residue theoremRelated: It helps justify closing contours when residues are used for Fourier-type integrals.Contour integrationRelated: It justifies discarding an arc when a contour is extended to infinity.ResidueRelated: It helps justify closing contours when residues are used to evaluate Fourier-type integrals.