A process of extending the region in which a Complex Function is defined.
See also Monodromy Theorem, Permanence of Algebraic Form, Permanence of Mathematical Relations Principle
References
Arfken, G. Mathematical Methods for Physicists, 3rd ed. Orlando, FL: Academic Press, pp. 378-380, 1985.
Morse, P. M. and Feshbach, H. Methods of Theoretical Physics, Part I. New York: McGraw-Hill,
pp. 389-390 and 392-398, 1953.