John Wallis(redirected from Arithmetica Infinitorum)
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.