Resumen de Thickness of the unit sphere, l1-types, and the almost Daugavet property

Vladimir Kadets, Varvara Shepelska, Dirk Werner

• We study those Banach spaces X for which SX does not admit a finite ?-net consisting of elements of SX for any ? < 2. We give characterisations of this class of spaces in terms of l1-type sequences and in terms of the almost Daugavet property. The main result of the paper is: a separable Banach space X is isomorphic to a space from this class if and only if X contains an isomorphic copy of l1.