  The formalism of reduced quantum electrodynamics is generalized to the case
of heterostructures composed of few atomically thick layers and the
corresponding effective (2+1)-dimensional gauge theory is formulated. This
dimensionally reduced theory describes charged fermions confined to $N$ planes
and contains $N$ vector fields with Maxwell`s action modified by non-local form
factors whose explicit form is determined. Taking into account the polarization
function, the explicit formulae for the screened electromagnetic interaction
are presented in the case of two and three layers. For a heterostructure with
two atomically thick layers and charged fermions described by the massless
Dirac equation, the dynamical gap generation of the excitonic type is studied.
It is found that additional screening due to the second layer increases the
value of the critical coupling constant for the gap generation compared to that
in graphene.
