Let S be a nonunital commutative semigroup, an involution, and the set of complex numbers. In this paper, first we determine the general solutions of Wilson’s generalizations of d’Alembert’s functional equations and on nonunital commutative semigroups, and then using the solutions of these equations we solve a number of other functional equations on more general domains.
"Solution of Several Functional Equations on Nonunital Semigroups Using Wilson’s Functional Equations with Involution." Abstr. Appl. Anal. 2014 1 - 9, 2014. https://doi.org/10.1155/2014/463918