K. S. S. Nambooripad

K. S. S. Nambooripad (6 April 1935 – 4 January 2020) was an Indian mathematician who made fundamental contributions to the structure theory of regular semigroups. Nambooripad was also instrumental in popularising the TeX software in India and also in introducing and championing the cause of the free software movement in India.

He was with the Department of Mathematics, University of Kerala, since 1976. He served the department as its Head from 1983 until his retirement from University service in 1995. After retirement, he was associated with the academic and research activities of the Center for Mathematical Sciences, Thiruvananthapuram in various capacities.

He died on January 4, 2020, in Thiruvananthapuram, at the age of 84. He obtained the BSc(Hons) degree of University of Kerala from Maharaja's College, Ernakulam, in 1956. He spent a few years teaching mathematics in some privately managed colleges A full treatment of the theory was published as a single paper number of the Memoirs of American mathematical Society in 1979. "In the mid 70s A. H. Clifford became very much excited by the work of Nambooripad on the structure of regular semigroups in terms of idempotent ordering and sandwich matrices and wrote several expository papers on Nambooripad structure theorem for regular semigroups".

He later developed an alternative approach to describe the structure of regular semigroups. This particular work utilizes the abstract theory of cross-connections to provide a useful framework for studying various classes of regular semigroups.

As a TeX populariser TeX was introduced into Kerala by Nambooripad. After a visit to the United States in early 1990s, he brought the TeX programme to Kerala in fourteen floppy disks. Nambooripad encouraged his students to learn and use TeX, especially for preparing their theses. One of his students was E. Krishnan, one of the authors of the LaTeX primer2 published as an electronic book by the Indian TeX User Group. Krishnan also played an important role in establishing the Free Software Foundation of India. Another person inspired by Nambooripad was Chandroth Vasudevan Radhakrishnan who is running a company called River Valley Technologies since 1995 for typesetting of scientific journals and books. Nambooripad was the prime catalyst for the formation of Indian TeX Users Group in 1998. He was the inaugural Chairman of the Group.