Miscellany

         t0       t0 t1       t0 t2       t0 t1 t2
{-m0 + ------ + --------- + --------- + ------------, 
       1 + t0   1 + t0 t1   1 + t0 t2   1 + t0 t1 t2
 
          t0 t1       t0 t1 t2            t0 t2       t0 t1 t2
  -m1 + --------- + ------------, -m2 + --------- + ------------}
        1 + t0 t1   1 + t0 t1 t2        1 + t0 t2   1 + t0 t1 t2

t's are free variables