Effectivity and Complexity Results in Hilbert's 17th problem Marie-Françoise Roy Université de Rennes 1, France

55 mins 40 secs,  201.11 MB,  iPod Video  480x270,  29.97 fps,  44100 Hz,  493.26 kbits/sec
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Description: Roy, M
Wednesday 28th June 2017 - 11:00 to 12:00
 
Created: 2017-07-20 13:05
Collection: Big proof
Publisher: Isaac Newton Institute
Copyright: Roy, M
Language: eng (English)
Distribution: World     (downloadable)
Explicit content: No
Aspect Ratio: 16:9
Screencast: No
Bumper: UCS Default
Trailer: UCS Default
 
Abstract: Hilbert 17th problem asks whether a polynomial taking only non-negative values is a sum of squares (in the field of rational functions). Its positive solution around 1925 by Artin does not make it possible to construct the sum of squares. Since then, some progress made it possible to give such contructions and to bound the degrees of the polynomials appearing in the sum of squares. An explicit recent proof gives elementary recursive degree bounds. The method of construction illustrates the current renewal of constructive algebra.
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