.nr PS 9.nr VS 11....ND "Revised  April, 1977".EQdelim $$gsize 9.EN....TR 17.TLA System for Typesetting Mathematics.AUBrian W. Kernighan and Lorinda L. Cherry.AI.MH.AB.PPThis paper describes the design and implementationof a system for typesetting mathematics.The language has been designed to be easy to learnand to useby people(for example, secretaries and mathematical typists)who know neither mathematics nor typesetting.Experience indicates that the language canbe learned in an hour or so,for it has few rules and fewer exceptions.For typical expressions,the size and font changes, positioning, line drawing,and the like necessary to print according to mathematical conventionsare all done automatically.For example,the input.sp 4p.cesum from i=0 to infinity x sub i = pi over 2.sp 4pproduces.EQsum from i=0 to infinity x sub i = pi over 2.EN.PPThe syntax of the language is specified by a smallcontext-free grammar;a compiler-compiler is used to make a compilerthat translates this language into typesetting commands.Output may be produced on either a phototypesetteror on a terminal with forward and reverse half-line motions.The system interfaces directly with text formatting programs,so mixtures of text and mathematics may be handled simply..LP.LP.PPThis paper is a revision of a paper originally published inCACM, March, 1975..AE