Extremizers in Soprunov and Zvavitch's Bezout inequalities for mixed volumes

In [20], I. Soprunov and A. Zvavitch have translated the Bezout inequalities (from Algebraic Geometry) into inequalities of mixed volumes satisfied by the simplex. They conjecture this set of inequalities characterizes the simplex, among all convex bodies in Rⁿ. Together with C. Saroglou, they proved the characterization among all polytopes [17] and, for a larger set of inequalities, among all convex bodies [18]. The conjecture remains open for n≥4. In this work, we investigate necessary conditions on the structure of the boundary of a convex body K, for K to satisfy all inequalities. In particular, we obtain a new solution of the 3-dimensional case.