` ` ` ` ` `EQN
is a
program for typesetting mathematics
on the Graphics Systems phototypesetters on
UNIX
and
GCOS.` `
The
EQN
language was designed to be easy to use
by people who know neither mathematics
nor typesetting.` `
Thus
EQN
knows relatively little about mathematics.` `
In particular, mathematical symbols like
+, -, ×, parentheses, and so on have no special meanings.` `
EQN
is quite happy to set garbage (but it will look good).` `

` ` ` ` ` `EQN
works as a preprocessor for the typesetter formatter,
TROFF[1],
so the normal mode of operation is to prepare
a document with both mathematics and ordinary text
interspersed,
and let
EQN
set the mathematics while
TROFF
does the body of the text.` `

` ` ` ` ` `On
UNIX,
EQN
will also produce mathematics on
DASI
and
GSI
terminals and on
Model 37 teletypes.` `
The input is identical, but you have to use the programs
NEQN
and
NROFF
instead of
EQN
and
TROFF.` `
Of course, some things won't look as good
because terminals
don't provide the variety of characters, sizes and fonts
that a typesetter does,
but the output is usually adequate for proofreading.` `

` ` ` ` ` `To use
EQN
on
UNIX,
eqn files | troff

GCOS
use is discussed in section 26.` `