José F. Fernando

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The tsunami disaster affecting the Indian Ocean region on Christmas 2004 demonstrated very clearly the shortcomings in tsunami detection, public warning processes as well as intergovernmental warning message exchange in the Indian Ocean region. The DEWS project, co-funded by the European Commission under the 6th Framework Programme, aims at strengthening(More)
Let k be a real field. We show that every non-negative homogeneous quadratic polynomial f (x 1 ,. .. , xn) with coefficients in the polynomial ring k[t] is a sum of 2n · τ (k) squares of linear forms, where τ (k) is the supre-mum of the levels of the finite non-real field extensions of k. From this result we deduce bounds for the Pythagoras numbers of(More)
We consider the 17th Hilbert Problem for global analytic functions in a modified form that involves infinite sums of squares. Then we prove a local-global principle for an analytic function to be a sum of squares. We deduce that an affirmative solution to the 17th Hilbert Problem for global analytic functions implies the finiteness of the Pythagoras number(More)