
theorem :: ClassFormula Class formula for finite groups
  for G being finite Group, f being FinSequence of conjugate_Classes G
  st f is one-to-one & rng f = conjugate_Classes G
  for c being FinSequence of NAT
  st len c = len f & for i being Element of NAT st i in dom c
  holds c.i = card (f.i) holds card G = Sum c by Th6;
