.EQ delim $$ .EN .th EQN I 5/31/77 .sh NAME eqn \*- typeset mathematics .sh SYNOPSIS .bd eqn [ file ] ... .sh DESCRIPTION .it Eqn is a .it troff\^\c (I) preprocessor for typesetting mathematics on the Graphics Systems, Inc. phototypesetter. Usage is almost always .s3 eqn file ... | troff .s3 If no files are specified, .it eqn reads 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 by .it eqn, so you can define them yourself in .it troff\^\c (I) to get centering, numbering, etc. All other lines are treated as comments, and passed through untouched. .s3 Spaces, tabs, new-lines, braces, double quotes, tilde, and circumflex are the only delimiters. Braces ``{}'' are used for grouping. Use tildes ``~'' to get extra spaces in an equation. .s3 .vs 13p Subscripts and superscripts are produced with the keywords .bd sub and .bd sup. Thus .it "x sub i" makes $x sub i$, .it "a sub i sup 2" produces $a sub i sup 2$, and .it "e sup {x sup 2 + y sup 2}" gives $e sup {x sup 2 + y sup 2}$. Fractions are made with .bd over. .it "a over b" is $a over b$ and .it "1 over sqrt {ax sup 2 +bx+c}" is $1 over sqrt {ax sup 2 +bx+c}$ ; .bd sqrt makes square roots. .s3 The keywords .bd from and .bd to introduce lower and upper limits on arbitrary things: $lim from {n-> inf} sum from 0 to n x sub i$ is made with .it "lim from {n-> inf} sum from 0 to n x sub i." Left and right brackets, braces, etc., of the right height are made with .bd left and .bd right: .it "left [ x sup 2 + y sup 2 over alpha right ] ~=~1" produces .if n .s3 $left [ x sup 2 + y sup 2 over alpha right ] ~=~1$. The .bd right clause is optional. .s3 Vertical piles of things are made with .bd "pile, lpile, cpile," and .bd rpile: .it "pile {a above b above c}" produces $pile {a above b above c}$. There can be an arbitrary number of elements in a pile. .bd lpile left-justifies, .bd pile and .bd cpile center, with different vertical spacing, and .bd rpile right justifies. .s3 .vs 12p Diacritical marks are made with .bd dot, .bd dotdot, .bd hat, .bd bar: .it "x hat = f(t) bar" is $x hat = f(t) bar$. Default sizes and fonts can be changed with .bd "size n" and various of .bd roman, .bd italic, and .bd bold. .s3 Keywords like .it sum .EQ ( sum ), .EN .it int .EQ ( int ), .EN .it inf .EQ ( inf ), .EN and shorthands like >=, .EQ (>=), .EN \*->, .EQ (->), .EN !=, .EQ ( != ) .EN are recognized. Spell out Greek letters in the desired case, as in .it "alpha, GAMMA." Mathematical words like .it sin, .it cos, .it log are made Roman automatically. .it Troff\^\c (I) four-character escapes like \\(ua (\(ua \*- for ``up arrow'') can be used anywhere. Strings enclosed in double quotes "..." are passed through untouched. .sh "SEE ALSO" .it "Typesetting Mathematics \\- User's Guide (2nd Edition)" by B. W. Kernighan and L. L. Cherry .br .it "New Graphic Symbols for EQN and NEQN" by C. Scrocca .br .it "N\s-2ROFF/TROFF\s0 User's Manual" by J. F. Ossanna .br troff(I), neqn(I) .sh 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.