U+2A13 "⨓" Line Integration with Semicircular Path Around Pole Unicode Character

U+2A13 "⨓" Line Integration with Semicircular Path Around Pole is a mathematical symbol used in complex analysis to denote a specific type of contour integral. In this notation, the integration path consists of a straight line segment that approaches a singularity, combined with a semicircular detour that goes around a pole to avoid it, often as part of a larger closed contour for evaluating integrals via the residue theorem. The symbol compactly represents the process of integrating along a line while circumventing a point where the function is not analytic, making it a valuable tool for expressing calculations in physics and engineering, particularly in the study of Fourier transforms and Cauchy principal value integrals.