for FMT being non empty FMT_Space_Str st FMT is Fo_filled & ( for A, B being Subset of FMT holds (A \/ B) ^Fodelta = (A ^Fodelta) \/ (B ^Fodelta) ) holds
for x being Element of FMT
for V1, V2 being Subset of FMT st V1 in U_FMT x & V2 in U_FMT x holds
ex W being Subset of FMT st
( W in U_FMT x & W c= V1 /\ V2 )