José Luis Massera (

Genoa Genoa ( ; ; ) is a city in and the capital of the Italian region of Liguria, and the sixth-largest city in Italy. As of 2025, 563,947 people live within the city's administrative limits. While its metropolitan city has 818,651 inhabitan ...

, Italy, June 8, 1915 –

Montevideo Montevideo (, ; ) is the capital city, capital and List of cities in Uruguay, largest city of Uruguay. According to the 2023 census, the city proper has a population of 1,302,954 (about 37.2% of the country's total population) in an area of . M ...

, September 9, 2002) was a Uruguayan dissident and mathematician who researched the

stability Stability may refer to: Mathematics *Stability theory, the study of the stability of solutions to differential equations and dynamical systems ** Asymptotic stability ** Exponential stability ** Linear stability **Lyapunov stability ** Marginal s ...

of differential equations.

Massera's lemma In stability theory and nonlinear control, Massera's lemma, named after José Luis Massera, deals with the construction of the Lyapunov function to prove the stability of a dynamical system In mathematics, a dynamical system is a system in w ...

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 on

topology Topology (from the Greek language, Greek words , and ) is the branch of mathematics concerned with the properties of a Mathematical object, geometric object that are preserved under Continuous function, continuous Deformation theory, deformat ...

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. Massera developed new notions of stability, and published several foundational papers and an influential textbook. His results in on periodic differential equations have been heavily cited and are referred to as Massera's theorem. His work in and on the converse to Lyapunov's criterion is also influential, and contain the well known

. His textbook is also heavily cited. After military intervention in Uruguay in 1973, Massera was arrested on October 22, 1975 in Montevideo and was held in

solitary confinement Solitary confinement (also shortened to solitary) is a form of imprisonment in which an incarcerated person lives in a single Prison cell, cell with little or no contact with other people. It is a punitive tool used within the prison system to ...

for nearly a year. During this time he was subjected to repeated

torture Torture is the deliberate infliction of severe pain or suffering on a person for reasons including corporal punishment, punishment, forced confession, extracting a confession, interrogational torture, interrogation for information, or intimid ...

resulting in injuries including a fractured pelvis. In October 1976 he was taken from solitary confinement, tried and convicted for "subversive association", and given a 24-year prison sentence. On June 22, 1979, as a consequence of a proposal put forward by Gaetano Fichera and unanimously approved by the whole Mathematics Faculty Council of the

Sapienza University of Rome The Sapienza University of Rome (), formally the Università degli Studi di Roma "La Sapienza", abbreviated simply as Sapienza ('Wisdom'), is a Public university, public research university located in Rome, Italy. It was founded in 1303 and is ...

, he was awarded the

laurea In Italy, the ''laurea'' is the main post-secondary academic degree. The name originally referred literally to the laurel wreath, since ancient times a sign of honor and now worn by Italian students right after their official graduation ceremo ...

honoris causa An honorary degree is an academic degree for which a university (or other degree-awarding institution) has waived all of the usual requirements. It is also known by the Latin phrases ''honoris causa'' ("for the sake of the honour") or ''ad hono ...

while still being under conviction. He was released in 1984.

Honors

* The outer main-belt asteroid 10690 Massera, discovered by American astronomer Schelte Bus at the Australian

Siding Spring Observatory Siding Spring Observatory near Coonabarabran, New South Wales, Australia, part of the Research School of Astronomy & Astrophysics (RSAA) at the Australian National University (ANU), incorporates the Anglo-Australian Telescope along with a coll ...

in 1981, was named in his memory on 13 April 2017 ().

Selected works

* . * . * . *

References

Biographical references

*. 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 the

degrees, 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 the

was awarded. {{DEFAULTSORT:Massera, Jose Luis 1915 births 2002 deaths Italian emigrants to Uruguay 20th-century Uruguayan mathematicians Mathematical analysts Prisoners and detainees of Uruguay Science and technology in Uruguay Uruguayan communists University of the Republic (Uruguay) alumni Uruguayan prisoners and detainees Members of the Senate of Uruguay TWAS fellows