for X, Y, Z being non empty set
for R being RMembership_Func of X,Y
for S being RMembership_Func of Y,Z
for x being Element of X
for z being Element of Z holds (R (#) S) . (x,z) = "\/" ( { ((R . (x,y)) "/\" (S . (y,z))) where y is Element of Y : verum } ,(RealPoset [.0,1.]))