Bezout Inequality for Mixed volumes
Presenter
November 15, 2017
Keywords:
- Bezout Inequality
- Mixed volume
- Projections
- Convex Body
MSC:
- 52A39
- 52B11
Abstract
In this talk we will discuss the following analog of Bezout inequality for mixed volumes:
V(P1,…,Pr,Δn−r)Vn(Δ)r−1≤∏i=1rV(Pi,Δn−1) for 2≤r≤n.
We will show that the above inequality is true when $\Delta$ is an $n$-dimensional simplex and $P_1, \dots, P_r$ are convex bodies in ${\mathbb R}^n$. We present a conjecture that if the above inequality is true for all convex bodies $P_1, \dots, P_r$, then $\Delta$ must be an $n$-dimensional simplex. We will show that the conjecture is true for many special cases, for example, in ${\mathbb R}^2$ or if we assume that $\Delta$ is a convex polytope. Next we will discuss an isomorphic version of the Bezout inequality: what is the best constant $c(n,r)>0$ such that
V(P1,…,Pr,Δn−r)Vn(D)r−1≤c(n,r)∏i=1rV(Pi,Dn−1) for 2≤r≤n,
where $P_1, \dots, P_r, D$ are convex bodies in ${\mathbb R}^n.$ Finally, we will present a connection of the above inequality to inequalities on the volume of orthogonal projections of convex bodies as well as inequalities for zonoids.