An application of John ellipsoids to the Szego kernel on unbounded convex domains

Abstract: We use convex geometry tools, in particular John ellipsoids, to obtain a size estimate for the Szeg\H{o} kernel on the boundary of a class of unbounded convex domains in $\mathbb{C}^n.$ Given a polynomial $b:\mathbb{R}^n \rightarrow \mathbb{R}$ satisfying a certain growth condition, we consider domains of the type $\Omega_b = { z\in\mathbb{C}^{n+1}\,:\, {\rm Im}[z_{n+1}] > b({\rm Re}[z_1],\ldots,{\rm Re}[z_n]) }.$