- excess_vars(+Term, +ExistVarTerm, +AddVarList, -VarList)
- Returns in VarList the list of (free) variables found in Term
concatenated to the end of AddVarList. (In normal usage AddVarList
is passed in as an empty list.) ExistVarTerm is a term containing
variables assumed to be quantified in Term so none of these
variables are returned in the resulting list (unless they are in
AddVarList.) Subterms of Term of the form
(VarTerm^SubTerm) are
treated specially: all variables in VarTerm are assumed to be
quantified in SubTerm, and so no occurrence of these variables in
SubTerm is collected into the resulting list.
