Volume IV of the Collected Works of V.I. Arnold includes papers written mostly during the period from 1980 to 1985. Arnold’s work of this period is so multifaceted that it is almost impossible to give a single unifying theme for it. It ranges from properties of integral convex polygons to the large-scale structure of the Universe. Also during this period Arnold wrote eight papers related to magnetic dynamo problems, which were included in Volume II, mostly devoted to hydrodynamics. Thus the topic of singularities in symplectic and contact geometry was chosen only as a “marker” for this volume. weiterlesen