Totally nonnegative Grassmannians, Grassmann necklaces, and quiver Grassmannians

Abstract Postnikov constructed a cellular decomposition of the totally nonnegative Grassmannians. The poset cells can be described (in particular) via Grassmann necklaces. We study certain quiver Grassmannians for cyclic admitting decomposition, whose are naturally labeled by show that posets coincide with reversed cell investigate algebro-geometric and combinatorial properties these In particular, we describe irreducible components, action automorphism groups underlying representations, moment graphs. also construct resolution singularities each component; resolutions defined as an extended quiver.