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« A Necessary and Sufficient Condition for $k$-transversals

A Necessary and Sufficient Condition for $k$-transversals

March 31, 2025, 2:00 PM - 3:00 PM

Location:

Conference Room 705

Rutgers University

Hill Center

110 Frelinghuysen Rd

Piscataway, NJ 08854

Daniel McGinnis, Princeton University

We solve a long-standing open problem posed by Goodman and Pollack in 1988 by establishing a necessary and sufficient condition for a finite family of convex sets in $mathbb{R}^d$ to admit a $k$-transversal (a $k$-dimensional affine subspace that intersects each set) for any $0 le k le d-1$. This result is a common generalization of Helly's theorem ($k=0$) and the Goodman-Pollack-Wenger theorem ($k=d-1$).

This is joint work with Nikola Sadovek.