theorem Th26:
  s9 is convergent & s is convergent & (lim s)<>0c & s is non-zero
  implies s9/"s is convergent
proof
  assume that
A1: s9 is convergent and
A2: s is convergent & (lim s)<>0c & s is non-zero;
  s" is convergent by A2,Th23;
  hence thesis by A1;
end;
