Semidefinite Programming and Euclidean Distance Matrix Completions Henry Wolkowicz (with Abdo Alfakih) Department of Combinatorics and Optimization University of Waterloo Waterloo, Ontario N2L 3G1 Abstract: Suppose we are given a partial symmetric nonnegative matrix $A$ with zero diagonal, and certain elements fixed. The Euclidean matrix completion problem consists in finding numbers for the unspecified (free) elements in order to make $A$ a Euclidean distance matrix. These problems have many applications and have been extensively studied. Much is known in terms of existence of completions. In this talk we will transform the problem into an approximate completion problem. We will show that this transformation allows for efficient solutions using semidefinite programming and interior-point techniques.