reserve x,y for object,X,Y for set;
reserve M for Pnet;

theorem
  the carrier of Tempty_f_net(X) = X &
  the carrier' of Tempty_f_net(X) = {} & Flow Tempty_f_net(X) = {}
proof
  Tempty_f_net(X) = PT_net_Str (# X, {}, {}(X,{}), {}({},X) #)
   by Def1,XBOOLE_1:65;
  hence thesis;
end;
