theorem
  QuantNbr(Ex(x,p)) = QuantNbr(p)+1
proof
  QuantNbr(Ex(x,p)) = QuantNbr('not' All(x,'not' p)) by QC_LANG2:def 5
    .= QuantNbr(All(x,'not' p)) by CQC_SIM1:16
    .= QuantNbr('not' p) + 1 by CQC_SIM1:18;
  hence thesis by CQC_SIM1:16;
end;
