Lower bounds on mapping content and quantitative factorization through trees

We give a simple quantitative condition, involving the “mapping content” of Azzam–Schul, which implies that a Lipschitz map from a Euclidean space to a metric space must be close to factoring through a tree. Using results of Azzam–Schul and the present authors, this gives simple checkable conditions for a Lipschitz map to have a large piece of its domain on which it behaves like an orthogonal projection. The proof involves new lower bounds and continuity statements for mapping content, and relies on a “qualitative” version of the main theorem recently proven by Esmayli–Hajłasz.