theorem Th01:
  for p,q,r being Point of TOP-REAL 3 holds
  |{p,q,r}| = |{r,p,q}| & |{p,q,r}| = |{q,r,p}|
  proof
    let p,q,r be Point of TOP-REAL 3;
    thus |{p,q,r}| = - |{p,r,q}| by ANPROJ_8:29
                  .= |{r,p,q}| by ANPROJ_8:30;
    thus |{p,q,r}| = - |{q,p,r}| by ANPROJ_8:30
                  .= |{q,r,p}| by ANPROJ_8:29;
  end;
