code: public boolean containsExclusive(double x, double y) {
  		// Note: This will return False, if envelope is empty, thus no need to
  		// call is_empty().
  		return x > xmin && x < xmax && y > ymin && y < ymax;
  	}
docs: Returns True if the envelope contains the point (boundary exclusive).
  @param x
  @param y
  @return True if this contains the point.