Entropy-Transport distances between unbalanced metric measure spaces
arXiv:2009.10636 · doi:10.1007/s00440-022-01159-4
Abstract
Inspired by the recent theory of Entropy-Transport problems and by the -distance of Sturm on normalised metric measure spaces, we define a new class of complete and separable distances between metric measure spaces of possibly different total mass. We provide several explicit examples of such distances, where a prominent role is played by a geodesic metric based on the Hellinger-Kantorovich distance. Moreover, we discuss some limiting cases of the theory, recovering the "pure transport" -distance and introducing a new class of "pure entropic" distances. We also study in detail the topology induced by such Entropy-Transport metrics, showing some compactness and stability results for metric measure spaces satisfying Ricci curvature lower bounds in a synthetic sense.
39 pages. Added a section with a comparison with the conic Gromov-Wasserstein distance. Some other minor improvements. Final version, to appear on "Probability Theory and Related Fields"