Sergio Spagnolo

Sergio Spagnolo was born in La Spezia on 14 June 1941. He grew up in Parma, where he attended the Guglielmo Marconi scientific high school and completed his studies in 1959. That year he won a place as a resident student at the Scuola Normale Superiore in Pisa. He graduated in mathematics from the University of Pisa in June 1963 with a thesis supervised by Aldo Andreotti, and received the Normale diploma in October 1963.

After two years as a postgraduate at the Normale, Spagnolo was an assistant there from 1965 to 1971, when he obtained the libera docenza in mathematical analysis and won a chair at the University of Cagliari. He taught at Parma from 1972 to 1974 and then returned to the University of Pisa as full professor of mathematical analysis, a post he held until 2011. From 1972 to 2002 he also taught an annual course at the Scuola Normale.

His 1968 paper on the convergence of solutions of parabolic and elliptic equations introduced G-convergence, named for its link with the convergence of Green's functions, and his 1973 paper with Ennio De Giorgi on the convergence of energy integrals developed the theory further. With De Giorgi and Ferruccio Colombini he showed in 1978 and 1979 that hyperbolic equations with coefficients depending only on time are well posed under suitable regularity, and gave a celebrated example of non existence when that regularity fails. He went on to study weakly hyperbolic Cauchy problems, systems with multiple characteristics, propagation of analyticity, the nonlinear Kirchhoff equation and local solvability in Gevrey classes, and lectured at the Collège de France, the Courant Institute, Imperial College, the Fields Institute and universities across Europe, Asia and the Americas.

He directed the Leonida Tonelli Mathematical Institute in 1976 and 1977, sat on the scientific council of the CNR group GNAFA from 1974 to 1997, on the scientific commission of the Italian Mathematical Union from 1985 to 1988 and on the board of INdAM from 1990 to 1994, and chaired the Pisa doctorate in mathematics from 2000 to 2003. He co-edited the selected works of Carlo Miranda (1992), the Selected Papers of Ennio De Giorgi (Springer, 2006) and the volume Scripta volant, verba manent (2008) on De Giorgi.

Spagnolo was married to Laura, and they had four children, Paolo, Maddalena, Matteo and Francesca, as well as grandchildren. Although his working life was centred on Pisa, he kept close ties with Parma, the city of his youth. His colleagues in Pisa recalled a deep friendship with Ennio De Giorgi that accompanied their scientific collaboration over many years.

Sergio Spagnolo died in Parma on Friday 23 October 2026, at the age of 85. His death was announced by his wife and children, and the University of Pisa and its Department of Mathematics published a tribute. His funeral took place on 26 October 2026 in the crypt of Parma Cathedral.

G-convergence, which Spagnolo introduced, became a central tool in the calculus of variations and in homogenisation, the mathematics of materials with fine microstructure, and inspired De Giorgi's later Gamma convergence. His results with Colombini and De Giorgi remain standard references on weakly hyperbolic equations. Through his teaching at Pisa and the Normale he trained students including Piero D'Ancona, and the University of Pisa remembered him as a mathematician whose work revealed deep links between the structure of equations and the behaviour of their solutions.