for C being FormalContext
for CP being strict FormalConcept of C holds "/\" ( { ConceptStr(# O,A #) where O is Subset of the carrier of C, A is Subset of the carrier' of C : ex a being Attribute of C st
( a in the Intent of CP & O = (AttributeDerivation C) . {a} & A = (ObjectDerivation C) . ((AttributeDerivation C) . {a}) ) } ,(ConceptLattice C)) = CP