Massera's lemma is named after him. He published over 40 papers during 1940–1970. A militant Communist, he was a political prisoner during 1975–1984. In the 1930s,Julio Rey Pastor gave regular weekend lectures ontopology in Montevideo to a group that included Massera. Stimulated by contact with Argentine mathematics, the 1950s saw Uruguay develop a fine school in mathematics, of which Massera was very much a part.[3]
Massera developed new notions of stability, and published several foundational papers and an influential textbook. His results in (Massera 1950) on periodic differential equations have been heavily cited and are referred to asMassera's theorem. His work in (Massera 1949) and (Massera 1956) on the converse toLyapunov's criterion is also influential, and contain the well knownMassera's lemma. His textbook (Massera & Schäffer 1966) is also heavily cited.
After military intervention in Uruguay in 1973,[3] Massera was arrested on October 22, 1975 in Montevideo and was held insolitary confinement for nearly a year. During this time he was subjected to repeatedtorture resulting in injuries including afractured pelvis. In October 1976 he was taken from solitary confinement, tried and convicted for "subversive association", and given a 24-year prison sentence.[4] On June 22, 1979, as a consequence of a proposal put forward byGaetano Fichera and unanimously approved by the whole Mathematics Faculty Council of theSapienza University of Rome,[5] he was awarded thelaureahonoris causa while still being under conviction.[6] He was released in 1984.[7]
Massera, José Luis; Schäffer, Juan Jorge (1966),Linear differential equations and function spaces, Pure and Applied Mathematics, Vol. 21, Boston, MA:Academic Press,MR0212324,Zbl0243.34107
Vernacchia-Galli, Jole (1986), "José Luis Massera",Regesto delle lauree honoris causa dal 1944 al 1985, Studi e Fonti per la storia dell'Università di Roma (in Italian and Spanish), vol. 10, Roma: Edizioni Dell'Ateneo, pp. 559–605. The "regest of honoris causa degrees from 1944 to 1985" (English translation of the title) is a detailed and carefully commented regest of all the documents of the official archive of the Sapienza University of Rome pertaining to thehonoris causadegrees, awarded or not. It includes all the awarding proposals submitted during the considered period, detailed presentations of the work of the candidate, if available, and precise references to related articles published on Italian newspapers and magazines, if thelaurea was awarded.
