Changes by: Aleksey Nogin (nogin at cs.caltech.edu)
Date: 1998-08-08 11:47:15 -0700 (Sat, 08 Aug 1998)
Revision: 2426
Log message:
It seems better to have a separate "special" form for FO-vars.
Right now SO vars are kept in "ugly" form,
but we may create a new "special" form for them later.
Important: mk_so_var v [] creates an "ugly" 0-ary SO var which is different
from FO var: it has no free variables and is not recognized by is_var_term