for g1, g2 being Real for X being real-memberedset st ( for r being Real st r in X holds r <= g1 ) & ( for s being Real st 0< s holds ex r being Real st ( r in X & g1 - s < r ) ) & ( for r being Real st r in X holds r <= g2 ) & ( for s being Real st 0< s holds ex r being Real st ( r in X & g2 - s < r ) ) holds g1 = g2