@(#)g4 6.2 (Berkeley) 04/17/91
.SC "A Large Example"
Here is the complete source for the three display equations in the abstract of this guide.
.vs -2
.EQ I
G(z)~mark =~ e sup { ln ~ G(z) }
~=~ exp left (
sum from k>=1 {S sub k z sup k} over k right )
~=~ prod from k>=1 e sup {S sub k z sup k /k}
.EN
.EQ I
lineup = left ( 1 + S sub 1 z +
{ S sub 1 sup 2 z sup 2 } over 2! + ... right )
left ( 1+ { S sub 2 z sup 2 } over 2
+ { S sub 2 sup 2 z sup 4 } over { 2 sup 2 cdot 2! }
+ ... right ) ...
.EN
.EQ I
lineup = sum from m>=0 left (
sum from
pile { k sub 1 ,k sub 2 ,..., k sub m >=0
above
k sub 1 +2k sub 2 + ... +mk sub m =m}
{ S sub 1 sup {k sub 1} } over {1 sup k sub 1 k sub 1 ! } ~
{ S sub 2 sup {k sub 2} } over {2 sup k sub 2 k sub 2 ! } ~
...
{ S sub m sup {k sub m} } over {m sup k sub m k sub m ! }
right ) z sup m
.EN
.vs +2
.SC "Keywords, Precedences, Etc."
If you don't use braces, C EQN will do operations in the order shown in this list.
1 3 dyad vec under bar tilde hat dot dotdot fwd back down up fat roman italic bold size sub sup sqrt over from to
2 These operations group to the left:
1 over sqrt left right
2 All others group to the right.
Digits, parentheses, brackets, punctuation marks, and these mathematical words are converted to Roman font when encountered:
1 sin cos tan sinh cosh tanh arc max min lim log ln exp Re Im and if for det
2 These character sequences are recognized and translated as shown.
.tr -- >= $>=$ <= $<=$ == $==$ != $!=$ +- $+-$ -> $->$ <- $<-$ << $<<$ >> $>>$ inf $inf$ partial $partial$ half $half$ prime $prime$ approx $approx$ nothing $nothing$ cdot $cdot$ times $times$ del $del$ grad $grad$ ... $...$ ,..., $,...,$ sum $sum$ int $int$ prod $prod$ union $union$ inter $inter$.tr --
To obtain Greek letters, simply spell them out in whatever case you want:
DELTA $DELTA$ iota $iota$ GAMMA $GAMMA$ kappa $kappa$ LAMBDA $LAMBDA$ lambda $lambda$ OMEGA $OMEGA$ mu $mu$ PHI $PHI$ nu $nu$ PI $PI$ omega $omega$ PSI $PSI$ omicron $omicron$ SIGMA $SIGMA$ phi $phi$ THETA $THETA$ pi $pi$ UPSILON $UPSILON$ psi $psi$ XI $XI$ rho $rho$ alpha $alpha$ sigma $sigma$ beta $beta$ tau $tau$ chi $chi$ theta $theta$ delta $delta$ upsilon $upsilon$ epsilon $epsilon$ xi $xi$ eta $eta$ zeta $zeta$ gamma $gamma$
These are all the words known to C EQN (except for characters with names), together with the section where they are discussed.
above 17, 18 lpile 17
back 21 mark 15
bar 13 matrix 18
bold 12 ndefine 20
ccol 18 over 9
col 18 pile 17
cpile 17 rcol 18
define 20 right 16
delim 19 roman 12
dot 13 rpile 17
dotdot 13 size 12
down 21 sqrt 10
dyad 13 sub 7
fat 12 sup 7
font 12 tdefine 20
from 11 tilde 13
fwd 21 to 11
gfont 12 under 13
gsize 12 up 21
hat 13 vec 13
italic 12 ~, ^ 4, 6
lcol 18 { } 8
left 16 "..." 8, 14
lineup 15
.SC Troubleshooting
If you make a mistake in an equation, like leaving out a brace (very common) or having one too many (very common) or having a .ul sup with nothing before it (common), C EQN will tell you with the message
1 2 syntax error between lines x and y, file z
2 where .ul x and .ul y are approximately the lines between which the trouble occurred, and .ul z is the name of the file in question. The line numbers are approximate _ look nearby as well. There are also self-explanatory messages that arise if you leave out a quote or try to run C EQN on a non-existent file.
If you want to check a document before actually printing it (on C UNIX only),
2 will throw away the output but print the messages.
If you use something like dollar signs as delimiters, it is easy to leave one out. This causes very strange troubles. The program .ul checkeq checks for misplaced or missing dollar signs and similar troubles.
In-line equations can only be so big because of an internal buffer in C TROFF . If you get a message ``word overflow'', you have exceeded this limit. If you print the equation as a displayed equation this message will usually go away. The message ``line overflow'' indicates you have exceeded an even bigger buffer. The only cure for this is to break the equation into two separate ones.
On a related topic, C EQN does not break equations by itself _ you must split long equations up across multiple lines by yourself, marking each by a separate C .EQ ...\& C .EN sequence. C EQN does warn about equations that are too long to fit on one line.