EQN(I) 2/22/74 EQN(I) NAME eqn - typeset mathematics SYNOPSISeqn[ file ] ... DESCRIPTIONEqnis a troff (I) preprocessor for typesetting mathematics on the Graphics Systems phototypesetter. Usage is almost always eqn file ... | troff If no files are specified,eqnreads from the standard input. A line beginning with ``.EQ'' marks the start of an equation; the end of an equation is marked by a line beginning with ``.EN''. Neither of these lines is altered or defined byeqn, so you can define them yourself to get centering, numbering, etc. All other lines are treated as comments, and passed through untouched. Spaces, tabs, newlines, braces, double quotes, tilde and circumflex are the only delimiters. Braces ``{}'' are used for grouping. Use tildes ``~'' to get extra spaces in an equation. Subscripts and superscripts are produced with the keywordssubandsup. Thusxsubimakesxi,asubisup2produces 2 2 2ai, andesup{xsup2+ysup2} givesex+y. Fractionsaare made withover.aoverbis _ and1oversqrt{axsup2b1 +bx+c} is________.sqrtmakes square roots. \/ax2+bx+cThe keywordsfromandtointroduce lower and upper limits onnarbitrary things: lim Σxiis made withlimfrom{n->inf}n->oo0sumfrom0tonxsubi. Left and right brackets, braces, etc., of the right height are made withleftandright:left[xsup2+ysup2overalpharight] ~=~1produces | |y2 |x2+ __| = 1. Therightclause is optional. α | | Vertical piles of things are made withpile,lpile,cpile,aandrpile:pile{aabovebabovec} producesb. There cancbe an arbitrary number of elements in a pile.lpileleft- justifies,pileandcpilecenter, with different vertical spacing, andrpileright justifies. Diacritical marks are made withdot,dotdot,hat,bar:xdot. ____ =f(t)barisx=f(t). Default sizes and fonts can be changed withsizenand various ofroman,italic, andbold. Keywords likesum(Σ)int(∫)inf(oo) and shorthands like >= (>) -> (->), != (≠), are recognized. Spell out Greek letters in the desired case, as inalpha,GAMMA. Mathematical words like sin, cos, log are made Roman automatically. Troff (I) four-character escapes like \(bs (o) can be used anywhere. Strings enclosed in double quotes "..." are passed through untouched. SEE ALSO A System for Typesetting Mathematics (Computer Science Technical Report #17, Bell Laboratories, 1974.) TROFF Users' Manual (internal memorandum) TROFF Made Trivial (internal memorandum) troff (I), neqn (I) BUGS Undoubtedly. Watch out for small or large point sizes - it's tuned too well for size 10. Be cautious if inserting horizontal or vertical motions, and of backslashes in general.