►Additiontheorems provide important connections between Mathieu functions with different parameters and in different coordinate systems.
They are analogous to the additiontheorems for Bessel functions (§10.23(ii)) and modified Bessel functions (§10.44(ii)).
…
§22.18(iv) Elliptic Curves and the Jacobi–Abel AdditionTheorem
…
►With the identification , , the addition law (22.18.8) is transformed into the additiontheorem (22.8.1); see Akhiezer (1990, pp. 42, 45, 73–74) and McKean and Moll (1999, §§2.14, 2.16).
…