theorem Th35:
  All(x,p => q) is valid implies Ex(x,p) => Ex(x,q) is valid
proof
  assume
A1: All(x,p => q) is valid;
  All(x,p => q) => (Ex(x,p) => Ex(x,q)) is valid by Th34;
  hence thesis by A1,CQC_THE1:65;
end;
