Characterization of metric spaces whose free space is isometric to ${\ell }_1$

Aude Dalet, Pedro L. Kaufmann, Antonín Procházka

We characterize metric spaces whose Lipschitz free space is isometric to ${\ell }_1$. In particular, the Lipschitz free space over an ultrametric space is not isometric to ${\ell }_1(\Gamma )$…