THE INVERSION OF WHITEHEAD'S THEOREM ON CONVEX REGIONS Lubom\' \i r Klapka Abstract. In 1932 J. H. C. Whitehead [2] proved the existence of convex neighbourhoods with respect to the geodesic arcs corresponding to a given connection on a manifold. The present paper gives necessary and sufficient conditions for a set of paths to be the set of all geodesics of some connection. The main condition is the existence of convex neighbourhoods in a more general sense. Keywords. Linear connections, geodesics, convex regions. MS classification. 53B05, 53C05, 53C22.