Tight paths in convex geometric hypergraphs

In this paper, we prove a theorem on tight paths in convex geometric hypergraphs, which is asymptotically sharp in infinitely many cases. Our geometric theorem is a common generalization of early results of Hopf and Pannwitz, Sutherland, Kupitz and Perles for convex geometric graphs, as well as the classical Erd\H{o}s-Gallai Theorem for graphs. As a consequence, we obtain the first substantial improvement on the Tur'{a}n problem for tight paths in uniform hypergraphs.