José Luis Massera

Who was José Luis Massera?

José Luis Massera was an Uruguayan mathematician who researched the stability of differential equations.

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 on topology 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 Massera's lemma. 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 for nearly a year. During this time he was subjected to repeated torture resulting in injuries including a fractured pelvis.