#print
.LP
The "right" part of a left-right construction can be
omitted if it is not used; just leave that part out.
The main thing to watch out for is that now you will
need braces to enclose the entire construction, "left" and all -
otherwise neqn will not know where to stop in
figuring out how high the thing is.

For example, will
  left "{" a + b over c over d
produce the same output as
   { left "{" a } + b over c over d
Answer yes or no after experimenting.
#copyin
#user
#uncopyin
#match no
#log
#next
12.1e 10