Taking this, socionics also differs from other typologies in that it also includes a complementary Base-16 relationship set, with the intent of penning to paper the key social dynamic traits between grouped combinations of socionic types. Therefore, socionics could be considered to be within the realm of the science of social dynamics, intended to describe social behavior according to mathematical applications of Base-16, group theory, set logic, and reduction of the Gulenko-Jungian notation for socionics types to hexadecimal and Base-2 bitwise operation. While this mathematical approach is strictly theoretical and has been criticized for lack of empirical testing, systems theory has been the tool of socionics theorist, such as Gregory Reinin to derive theorical dichotomies within socionics theory. In 1985 Aušra Augustinavičiūtė acknowledged the mathematical theories of Reinin and wrote a book titled "The Theory of Reinin's Traits" to describe the mathematical processes of socionics theory. Mathematical methods have been a standard part of socionics theory since this time.