Mathematics Colloquium

Tel Aviv University

Monday, March 20, 2017
Schreiber 006
Vitali Milman
Tel Aviv University
"Irrational" convexity

Do we have enough examples of Convex Bodies? Is diversity of our standard examples enough to understand Convexity? In the talk we demonstrate many different constructions which are analogous to constructions of irrational numbers from rationals. We show, following Il. Molchanov, that the solutions of "quadratic" equations like Zo = Z + K always exists (where Zo is the polar body of Z; Z and K are convex compact bodies containing 0 in the interior). Then we show how the geometric mean may be defined for any convex compact bodies K and T (containing 0 into their interior). We also construct Ka for any centrally symmetric K and 0 < a < 1, and also Log K for K containing the euclidean ball D (and K = −K). Note, the power a cannot be above 1 in the definition of power! All these constructions may be considered also for the infinite dimensional setting, but this is outside the subject of the talk.

These results are joint with Liran Rotem.

Colloquium's homepage : www  |  Vitali Milman's homepage : www