 A leading international specialist in database theory, the Argentinian Alberto Mendelzon (1951–2005), also deserves a mention because of his key contribution to the theory of belief change. He obtained a B.Sc. from UBA as well as a M.S.E., a M.A., and a Ph.D. from Princeton University. From 1980 until his death, he taught at the University of Toronto. He also contributed to the creation of UBA’s computer science department in the early 1980s. In 1992 he published, together with Hirofumi Katsuno, a highly influential paper that addresses the issue of updating knowledge bases (Katsuno &amp; Mendelzon 1992). They distinguished between two kinds of modification to a knowledge base: update and revision. While the former consists in bringing the knowledge base up to date when the world it describes changes, the latter consists in modifying the knowledge base when new information about a static world is acquired. Mendelzon and Katsuno claimed that the AGM postulates describe only revision and hence that, in order to describe update, the AGM theory should be considerably modified by adding new postulates. (On Mendelzon’s work on belief change, see also Katsuno &amp; Mendelzon 1989 and 1991.)