Mathematician, born in Ancona, EC Italy. He was professor at Pisa, Turin, and Rome. In 1931 he was dismissed from his chair at Rome for refusing to sign an oath of allegiance to the Fascist government, and he spent most of the rest of his life abroad. He developed a general theory of functionals which strongly influenced modern calculus and analytical methods, and worked on integral equations, mathematical physics, and the mathematics of population change in biology.