reserve GX,GY for non empty TopSpace,
  x,y for Point of GX,
  r,s for Real;
reserve Q,P1,P2 for Subset of TOP-REAL 2;
reserve P for Subset of TOP-REAL 2;
reserve w1,w2 for Point of TOP-REAL 2;
reserve pa,pb for Point of TOP-REAL 2,
  s1,t1,s2,t2,s,t,s3,t3,s4,t4,s5,t5,s6,t6, l,sa,sd,ta,td for Real;
reserve s1a,t1a,s2a,t2a,s3a,t3a,sb,tb,sc,tc for Real;

theorem Th24:
  for s1,s2,t1,t2 holds { pq where pq is Point of TOP-REAL 2:
  not (s1<=pq`1 & pq`1<=s2 & t1<=pq`2 & pq`2<=t2)} is Subset of TOP-REAL 2
proof
  let s1,s2,t1,t2;
  { |[ sb,tb ]|:not (s1<=sb & sb<=s2 & t1<=tb & tb<=t2)}
  is Subset of TOP-REAL 2 by Lm2,Lm8;
  hence thesis by Th22;
end;
