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Chow–Lam recovery for Grassmannian subvarieties

Prove that a subvariety V ⊂ Gr_ℂ(k,n), defined by k(n−r)+1 generic linear forms in the Plücker coordinates, coincides with its Chow–Lam recovery W_V, as conjectured by Pratt–Ranestad (Conjecture 6.6).

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Background

Inspired by amplituhedron maps, Chow–Lam recovery asks whether a variety can be reconstructed from linear projections to smaller Grassmannians. The conjecture formulates a precise recovery criterion via the number of defining linear forms. Proving equality V = W_V would generalize classical Chow form reconstruction and solidify recovery methods in positive-geometry contexts.

References

Let $\mathcal{V}$ be a subvariety of the Grassmannian ${\rm Gr}\mathbb{C}(k,n)$ which is defined by $k(n-r)+1$ generic linear forms in the Pl\"ucker coordinates. Prove that $\mathcal{V}$ coincides with its Chow-Lam recovery $\mathcal{W}\mathcal{V}$. \hfill Conjecture 6.6.

What is Positive Geometry? (2502.12815 - Ranestad et al., 18 Feb 2025) in Open questions