theorem Th53: :: PSCOMP_1:53
for P being Subset of (TOP-REAL 2) holds
( (SW-corner P) `2 = (S-min P) `2 & (SW-corner P) `2 = (S-max P) `2 & (S-min P) `2 = (S-max P) `2 & (S-min P) `2 = (SE-corner P) `2 & (S-max P) `2 = (SE-corner P) `2 )