reserve n,m,k for Element of NAT,
  x,X for set,
  A1 for SetSequence of X,
  Si for SigmaField of X,
  XSeq for SetSequence of Si;
reserve Omega for non empty set,
  Sigma for SigmaField of Omega,
  ASeq for SetSequence of Sigma,
  P for Probability of Sigma;

theorem Th26:
  for C being thin of P holds C in COM(Sigma,P)
proof
  let C be thin of P;
  reconsider B = {} as Element of Sigma by PROB_1:4;
  B \/ C in COM(Sigma,P) by Def5;
  hence thesis;
end;
