text: #include <algorithm>
  #include <functional>
  #include <random>
  
  #include "check.hh"
  #include "interval.hh"
  #include "interval_algebra.hh"
  
  //------------------------------------------------------------------------------------------
  // Interval Lt
  // interval Lt(const interval& x, const interval& y) const;
  // void testLt() const;
  
  interval interval_algebra::Lt(const interval& x, const interval& y) const
  {
      return Gt(y, x);
  }
  
  void interval_algebra::testLt() const
  {
      check("test algebra Lt", Lt(interval(5), interval(6, 10)), interval(1));
      check("test algebra Lt", Lt(interval(2, 5), interval(0, 2)), interval(0));
      check("test algebra Lt", Lt(interval(-1, 1), interval(0, 10)), interval(0, 1));
  }
  