reserve S for Subset of TOP-REAL 2,
  C,C1,C2 for non empty compact Subset of TOP-REAL 2,
  p,q for Point of TOP-REAL 2;
reserve i,j,k for Nat,
  t,r1,r2,s1,s2 for Real;
reserve D1 for non vertical non empty compact Subset of TOP-REAL 2,
  D2 for non horizontal non empty compact Subset of TOP-REAL 2,
  D for non vertical non horizontal non empty compact Subset of TOP-REAL 2;
reserve s for rectangular FinSequence of TOP-REAL 2;

theorem
  s/.4 = S-min L~s & s/.4 = W-min L~s
proof
  consider D such that
A1: s = SpStSeq D by Def2;
A2: s/.4 = SW-corner D by A1,Th38;
  hence s/.4 = S-min L~s by A1,Th80;
  thus thesis by A1,A2,Th74;
end;
