Patrick D. F. Ion is an American mathematician whose main interest is in mathematical knowledge management.
Ion completed his dissertation on quantum field theory, "Topics in Constructive QFT", in 1972 at the University of London under the supervision of Ray Streater.
He continued to work in London, Groningen and Heidelberg in the field of quantum stochastics, q-analogues and the discrete Fourier transform in elementary geometry.
He was since then responsible for the decennial revisions of the Mathematics Subject Classification (MSC).
He is co-chair of the World Wide Web Consortium Math Working Group, where he developed the MathML specifications.