With the square eigenfunctions symmetry constraint, we introduce a new
extended matrix KP hierarchy and its Lax representation from the matrix KP
hierarchy by adding a new τB flow. The extended KP hierarchy contains two
time series tA and τB and eigenfunctions and adjoint
eigenfunctions as components. The extended matrix KP hierarchy and its
tA-reduction and τB reduction include two types of matrix KP hierarchy
with self-consistent sources and two types of (1+1)-dimensional reduced matrix
KP hierarchy with self-consistent sources. In particular, the first type and
second type of the 2+1 AKNS equation and the Davey-Stewartson equation with
self-consistent sources are deduced from the extended matrix KP hierarchy. The
generalized dressing approach for solving the extended matrix KP hierarchy is
proposed and some solutions are presented. The soliton solutions of two types
of 2+1-dimensional AKNS equation with self-consistent sources and two types of
Davey-Stewartson equation with self-consistent sources are studied.Comment: 17 page