The GAMM Committee l'or Efficient Numerìcal l\1ethods l'or Partial Differential Equations (GAMM FachausschuB "Effiziente Numerische Verf'ahren fìir Partielle Differentialgleichungen") organizes conferences and serninars on subjects concerning the algorit hmic treatment of partial differential equation problerns. The two flrst sernìnars "Efficient Solution of Elliptic Systems" 098S) and "Efficient Numerical Methods in Continuum Mechanìcs" (986) were followed by a third one, co-organized together with the GAMM Committee l'or Dlscre­ tizing Methods in Solid Mechanics and the special re search project SFB 2S "Vortex Flows in Aeronaut.ìcs" at the R\VTH Aachen, sponsor-ed by the Deutsche Forschungsgemeinschaft CDFGl. During the last decades PaneI Methods and Boundary Element Methods became a very efficient tool to selve numerìcally the integrai equations with surface or boundary singularity distributions in Aerodynamics and in Continuum Mechanics. First designed l'or ell iptic problems with linear partial dìfferent.ial equations, the different variants of the methods now apply to nonlinearities introduced by free vortex sheets or compressible flows and to time-dependent problems as wave propagation and non-stationary Flows. The seminar was attended by 47 scientists l'rom IO countrles. A greater part of the 22 papers presented at the seminar concerned t he different approaches l'or st.atlonary and non-stationary subsonic potential flows around aerodynamic configurations and propellers, inc1uding inverse methods l'or design problems.