Multiform total symmetry and parity functions

In recent letters, Biswas reported the existence of a special class of totally symmetric switching functions which remain invariant for all combinations of complemented and uncomplemented variables of symmetry, and also studied some of their properties. It is shown in this letter that these special symmetric functions are a particular class of linear functions known in literature as odd-parity functions and even-parity functions and form a subclass of totally symmetric functions showing multiform symmetry. Some of the relevant properties of these functions from the viewpoint of linear functions are also studied.