reserve p,p1,p2,q,r,F,G,G1,G2,H,H1,H2 for ZF-formula,
  x,x1,x2,y,y1,y2,z,z1,z2,s,t for Variable,
  a,X for set;
reserve M for non empty set,
  m,m9 for Element of M,
  v,v9 for Function of VAR,M;
reserve i,j for Element of NAT;

theorem Th136:
  not x in { 0,1,2,3,4 }
proof
  assume x in { 0,1,2,3,4 };
  then x in { 0,1 } \/ { 2,3,4 } by ENUMSET1:8;
  then x in { 0,1 } or x in { 2,3,4 } by XBOOLE_0:def 3;
  then
A1: x = 0 or x = 1 or x = 2 or x = 3 or x = 4 by ENUMSET1:def 1,TARSKI:def 2;
  x in VAR;
  then ex i st x = i & 5 <= i;
  hence contradiction by A1;
end;
