theorem Th8: :: WAYBEL_1:8

for S, T being non empty Poset
for g being Function of S,T
for d being Function of T,S holds
( [g,d] is Galois iff ( g is monotone & d is monotone & ( for t being Element of T
for s being Element of S holds
( t <= g . s iff d . t <= s ) ) ) )