  We introduce a new variant of dependence logic called Boolean dependence
logic. In Boolean dependence logic dependence atoms are of the type
=(x_1,...,x_n,\alpha), where \alpha is a Boolean variable. Intuitively, with
Boolean dependence atoms one can express quantification of relations, while
standard dependence atoms express quantification over functions.
  We compare the expressive power of Boolean dependence logic to dependence
logic and first-order logic enriched by partially-ordered connectives. We show
that the expressive power of Boolean dependence logic and dependence logic
coincide. We define natural syntactic fragments of Boolean dependence logic and
show that they coincide with the corresponding fragments of first-order logic
enriched by partially-ordered connectives with respect to expressive power. We
then show that the fragments form a strict hierarchy.
