public ShapeTileSimplex remove_border_line(int p_no){
  if (p_no < 0 || p_no >= lines_size()) {
    return this;
  }
  ArrayList<PlaLineInt> new_arr=new ArrayList<PlaLineInt>(lines_size());
  new_arr.addAll(lines_list);
  new_arr.remove(p_no);
  return new ShapeTileSimplex(new_arr);
}

public ShapeTileSimplex remove_border_line ( int p_no ) { if ( p_no < 0 || p_no >= lines_size ( ) ) { return this ; } ArrayList < PlaLineInt > new_arr = new ArrayList < PlaLineInt > ( lines_size ( ) ) ; new_arr . addAll ( lines_list ) ; new_arr . remove ( p_no ) ; return new ShapeTileSimplex ( new_arr ) ; }
enlarges the simplex by removing the edge line with index p_no . the result simplex may be unbounded .
