Tropical geometry and Newton-Okounkov cones for Grassmannian of planes from compactifications

Abstract

We construct a family of compactifications of the affine cone of the Grassmannian variety of 2-planes. We show that both the tropical variety of the Plücker ideal and familiar valuations associated to the construction of Newton-Okounkov bodies for the Grassmannian variety can be recovered from these compactifications. In this way, we unite various perspectives for constructing toric degenerations of flag varieties.

25 pages; we added a proof that the compactifications are Fano