John Wallis (23 November 1616 – 28 October 1703) was an English mathematician who is given partial credit for the development of infinitesimal calculus. Between 1643 and 1689 he served as chief cryptographer for Parliament and, later, the royal court. He is also credited with introducing the symbol ∞ for infinity. He similarly used 1/∞ for an infinitesimal. Asteroid31982 Johnwallis was named after him.
