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http://reply.papertrans.cn/1/43/4297/4297-32.png
Submitted on: 19 November 2007.
Revised on: 17 February 2008.
Accepted on: 28 March 2008.
___________________BULLETIN DE LA SOCIETE MATHEMATIQUE DE FRANCE
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Submitted on: 29 May 2010.
Revised on: 16 August 2010.
Accepted on: 23 September 2010.
___________________BULLETIN DE LA SOCIETE MATHEMATIQUE DE FRANCE
Submitted on: 22 August 2015.
Revised on: 08 December 2015.
Accepted on: 28 December 2015.
___________________BULLETIN DE LA SOCIETE MATHEMATIQUE DE FRANCE