Jaime A. Ponce de León was one of the earliest researchers to join what eventually became known as the 5D Space-Time-Matter Consortium. He made essential contributions to all parts of the theory, most notably in the discovery of a general cosmological solution that reduces to standard FLRW form on 4D hypersurfaces (1988), the derivation (with Paul Wesson) of the general form of the induced-matter energy-momentum tensor (1992), and the demonstration of equivalence between the STM and brane-world approaches (2001). He co-authored 14 articles with Wesson but worked in many other areas as well. The breadth of his interests can be appreciated from the subjects covered by his 44 arXiv posts since 2001.
It comes as a shock to learn via a notice posted online by the Faculty of Science at the University of Puerto Rico that Jaime died in September 2018. The notice tells us that he became professor in the Department of Physics in 1989 after obtaining BSc and MSc degrees in Physics and Mathematics from the Peoples’ Friendship University of Russia in Moscow (1974 and 1977), and earning his PhD in Physics from the Universidad Central de Venezuela in 1985. Along with Paul Wesson, Jaime Ponce de León was the driving force behind Space-Time-Matter theory. He will be sorely missed.