On the pythagoras numbers of real analytic set germs.

We Show that (i) the Pythagoras number of a real analytic set germ is the supremum of the Pythagoras numbers of the curve germs it contains, and (ii) every real analytic curve germ is contained in a real analytic surface germ with the same Pythagoras number (or Pythagoras number 2 if the curve is Py...

ver descrição completa

Detalhes bibliográficos
Autores: Fernando Galván, José Francisco, Ruiz Sancho, Jesús María
Formato: artículo
Fecha de publicación:2005
País:España
Recursos:Universidad Complutense de Madrid (UCM)
Repositorio:Docta Complutense
Idioma:inglés
OAI Identifier:oai:docta.ucm.es:20.500.14352/49907
Acesso em linha:https://hdl.handle.net/20.500.14352/49907
Access Level:acceso abierto
Palavra-chave:512.7
Pythagoras number
sum of squares
M. Artin’s approximation.
Geometria algebraica
1201.01 Geometría Algebraica
Descrição
Resumo:We Show that (i) the Pythagoras number of a real analytic set germ is the supremum of the Pythagoras numbers of the curve germs it contains, and (ii) every real analytic curve germ is contained in a real analytic surface germ with the same Pythagoras number (or Pythagoras number 2 if the curve is Pythagorean). This gives new examples and counterexamples concerning sums of squares and positive semidefinite analytic function germs.