reserve p,q,x,x1,x2,y,y1,y2,z,z1,z2 for set;
reserve A,B,V,X,X1,X2,Y,Y1,Y2,Z for set;
reserve C,C1,C2,D,D1,D2 for non empty set;

theorem
  for f being Function of X,D1 for g being Function of X,D2 holds pr1(D1
  ,D2)*<:f,g:> = f & pr2(D1,D2)*<:f,g:> = g by Th61;
