22 citations · 79 across the 19 of their papers we have counts for
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Reducing non-negativity over general semialgebraic sets to non-negativity over simple sets
Olga Kuryatnikova, Juan C. Vera, Luis F. Zuluaga
A non-negativity certificate (NNC) is a way to write a polynomial so that its non-negativity on a semialgebraic set becomes evident. Positivstellensätze (Psätze) guarantee the exis…
Equivalence and invariance of the chi and Hoffman constants of a matrix
Javier F. Pena, Juan C. Vera, Luis F. Zuluaga
We show that the following two condition measures of a full column rank matrix are identical: the chi constant and a signed Hoffman constant. This id…
New characterizations of Hoffman constants for systems of linear constraints
Javier Pena, Juan Vera, Luis Zuluaga
We give a characterization of the Hoffman constant of a system of linear constraints in {\em relative} to a {\em reference polyhedron} . The reference polyhe…
Generalizations of Schoenberg's theorem on positive definite kernels
Olga Kuryatnikova, Juan C. Vera
The seminal theorem of I.J. Schoenberg characterizes positive definite (p.d.) kernels on the unit sphere invariant under the automorphisms of the sphere. We obtain two ge…