Hanh Van Nguyen

Multilinear Multiplier Theorems and Applications

We obtain new multilinear multiplier theorems for symbols of restricted smoothness which lie locally in certain Sobolev spaces. We provide applications concerning the boundedness of the commutators of Calderón and Calderón–Coifman–Journé.

Computing the Distance Between Frames and Between Subspaces of a Hilbert Space

A fundamental notion in Hilbert space frame theory is to compute the distance between frames and the distance between subspaces of a Hilbert space. One space these problems arise is with a number of algorithms which serve to approximate frame operators or inverse operators [5]. There are six standard distance functions used in frame theory. In this paper we will establish the exact relationship between all of these distance functions.