code: static Geometry pointMinusPolygon_(Point point, Polygon polygon,
  			double tolerance, ProgressTracker progress_tracker) {
  		PolygonUtils.PiPResult result = PolygonUtils.isPointInPolygon2D(
  				polygon, point, tolerance);
  
  		if (result == PolygonUtils.PiPResult.PiPOutside)
  			return point;
  
  		return point.createInstance();
  	}
docs: these are special implementations, all others delegate to the topo-graph.