reserve A,A1,A2,B,B1,B2,C,O for Ordinal,
      R,S for Relation,
      a,b,c,o,l,r for object;

theorem Th8:
  Day(R,0) = Games 0
proof
  reconsider A=[{},{}] as Element of Games 0 by Th2,TARSKI:def 1;
  A1: L_A <<R, R_A;
  for x be object st x in L_A \/ R_A
  ex O be Ordinal st O in 0 & x in Day(R,O);
  then A in Day(R,0) by Th7,A1;
  hence thesis by Th2,ZFMISC_1:33;
end;
