Kolmogorov n-Widths of Function Classes Induced by a Non-Degenerate Differential Operator: A Convex Duality Approach

Patrick L. Combettes, Dinh Dũng

Let $P(D)$ be the differential operator induced by a polynomial $P$, and let $U_2^{[P]}$ be the class of multivariate periodic functions $f$ such that $\Vert P(D)(f){\Vert }_2\le 1$. The…