He was member of the Reviewing Body of the "Mathematical Reviews" (1963-1980), member of the Preparatory Committee for the Establishment of the University of Cyprus (1988-1992), chairman of the Selection Committee for the Mathematics and Statistics Department of the University of Cyprus (1990-1996), chairman of the Peer Review Group for the first Quality Assessment of Third Level Institutions in Greece (1995), and chairman of the Local Organising Committee of the 17th International Conference on General Relativity and Gravitation, held in Dublin at the RDS Convention Centre from 18 – 23 July 2004 (2001-2004). He was life member of the International Society on General Relativity and Gravitation, fellow of the Royal Astronomical Society, London (since 1963), and a patron (and past president) of the Irish Hellenic Society. He was a former pro-chancellor of Trinity College Dublin from 2010–2012. In 2012, he edited a book on Edward Hutchinson Synge with Denis Weaire and John F. Donegan.