QUERY: CREATE OPERATOR ## (
   leftarg = path,
   rightarg = path,
   procedure = path_inter,
   commutator = ##
);
QUERY: CREATE OPERATOR <% (
   leftarg = point,
   rightarg = circle,
   procedure = pt_in_circle,
   commutator = >=%
);
QUERY: CREATE OPERATOR @#@ (
   rightarg = int4,		
   procedure = int4fac
);
QUERY: CREATE OPERATOR #@# (
   leftarg = int4,		
   procedure = int4fac
);
QUERY: CREATE OPERATOR #%# (
   leftarg = int4,		
   procedure = int4fac
);