reserve Q,Q1,Q2 for multLoop;
reserve x,y,z,w,u,v for Element of Q;

theorem Th20:
  1.Q in Nucl Q
proof
  A1: 1.Q in Nucl_l Q by Th20a;
  1.Q in Nucl_m Q by Th20b;
  hence thesis by A1,Th12,Th20c;
end;
