+template<>
+string
+Interval_t<Moment>::T_to_string (Moment a)
+{
+ return a.to_string ();
+}
+
+template INTERVAL__INSTANTIATE (Moment);
+
+template<>
+Real
+Interval_t<Real>::linear_combination (Real x) const
+{
+ Drul_array<Real> da (at (LEFT), at (RIGHT));
+ return ::linear_combination (da, x);
+}