RT Journal Article T1 The δ̅ -approach to the dispersionless KP hierarchy A1 Konopelchenko, Boris A1 Martínez Alonso, Luis A1 Ragnisco, O. AB The dispersionless limit of the scalar nonlocal a-problem is derived. It is given by a special class of nonlinear first-order equations. A quasiclassical version of the partial derivative -dressing method is presented. It is shown that the algebraic formulation of dispersionless hierarchies can be expressed in terms of properties of Beltrami-type equations. The universal Whitham hierarchy and, in particular, the dispersionless KP hierarchy turn out to be rings of symmetries for the quasiclassical partial derivative -problem. PB IOP Publishing SN 0305-4470 YR 2001 FD 2001-11-30 LK https://hdl.handle.net/20.500.14352/59826 UL https://hdl.handle.net/20.500.14352/59826 LA eng NO ©2001 IOP Publishing Ltd.L Martínez Alonso is partially supported by CICYT proyecto PB98–0821. NO CICYT DS Docta Complutense RD 12 may 2025