  A Dp-brane can be regarded as a configuration of infinitely many
D(p-2k)-branes in bosonic string. We will show this property of D-branes in the
superstring case using the hybrid formalism. It is convenient to study the
boundary state for such D-branes to study such property between D-branes. We
show that the boundary state for a D3-brane in a constant self-dual gauge field
background can be expressed in terms of the boundary state for D-instantons in
the hybrid formalism.
