Wallis, John(wŏl`ĭs), 1616–1703, English mathematician. He was Savilian professor of geometry at Oxford from 1649. He systematized the use of formulas, introduced the symbol ∞ for infinity, and made a study of the quadrature of curves, which he recorded in Arithmetica infinitorum (1655). His collected mathematical works appeared in three volumes (1693–99). He wrote also on grammar, logic, theology, and cryptography.
Born Nov. 23, 1616, in Ashford, Kent; died Oct. 28, 1703, in Oxford. British mathematician.
Beginning in 1649, Wallis was a professor of geometry at Oxford University. He was one of the founders (1662) of the Royal Society of London. His principal work, Arithmetica infinitorum (1655), played an important role in the prehistory of integral calculus. Wallis found an expression for the number π, and he introduced the generally accepted sign (∞) to designate infinity.