  The paper proposes a way to add marketing into the standard threshold model
of social networks. Within this framework, the paper studies logical properties
of the influence relation between sets of agents in social networks. Two
different forms of this relation are considered: one for promotional marketing
and the other for preventive marketing. In each case a sound and complete
logical system describing properties of the influence relation is proposed.
Both systems could be viewed as extensions of Armstrong's axioms of functional
dependency from the database theory.
