The theory of functions of a complex variable, is the branch of mathematical analysis that investigates functions of complex numbers.

- Pakistan Mathematical SocietyThe PakMS was registered on 16th November 2001. The Society had to apply again for registration under the ACT XXI of 1860 to meet the requirement of the Pakistan Science Foundation for registration of the society with it. It was finally registered under this Act on 17th February 2003. Membership of the Society is
- American Mathematical SocietyThe American Mathematical Society has a bicameral governance structure consisting of the Council (created when the Society’s constitution was ratified in December 1889) and the Board of Trustees (created when the Society was incorporated in May 1923). These bodies have the ultimate responsibility and
- London Mathematical SocietyThe London Mathematical Society is the major UK learned society for mathematics. The Society's activities include publishing journals and books, providing grants to support mathematics and organising scientific meetings and lectures.

- European Mathematical SocietyThe European Mathematical Society is a learned society representing mathematicians throughout Europe. It promotes the development of all aspects of mathematics in Europe, in particular mathematical research, relations of mathematics to society, relations to European institutions, and mathematical
- Canadian Mathematical SocietiesThe Canadian Mathematical Society (CMS) was originally conceived in June 1945 as the Canadian Mathematical Congress. The founding members hoped that "this congress [would] be the beginning of important mathematical development in Canada". Seeking to end confusion with the quadrennial
- Mathematical Programming Societyinternational organization dedicated to the promotion and the maintenance of high professional standards in the subject of mathematical programming. It is incorporated as a non-profit tax-exempt scientific organization in the United States.