usr/lib/learn/eqn/L5.1h

#once #create message
.ND
.tr %$
.EQ
delim $$
.EN
.LP
One thing that you will occasionally need
is to be able to get a literal { or } in your
output, for an expression like
.EQ
{ "{" a + b "}" } over 2
.EN
The way to do this is to place the braces
that are really to appear ______\b\b\b\b\b\binside ______\b\b\b\b\b\bquotes,
like this:
   .EQ
   { "{" a + b "}" } over 2
   .EN
.br
The quotes temporarily turn off the special meaning
of the braces so that you can have them printed.

The file "Example" has a lot of square brackets in
it.  Modify them so they are all braces when they are
printed - so they look like this - then type "ready".
.pl 1
#once #create Ref
.LP
.EQ
f"{" x sub 1 ,..., x sub n "}" ~=~ "{" x sub 1 ,..., x sub n "}"
.EN
.pl 1
#once #create Example
.LP
.EQ
f[ x sub 1 ,..., x sub n ] ~=~ [ x sub 1 ,..., x sub n ]
.EN
.pl 1
#
#once neqn Ref | nroff >X1 &
#once neqn message Ref | nroff -T$term %s/tinyms -
#user
neqn Example | nroff >X2
#cmp X1 X2
#log
#next
6.1a 10