Collectivity in S-41

Supported in part by the EPSRC (UK) and by the European Union under Contract No. RII3-CT- 2004-506065. A.J. acknowledgesfinancial support from the m Spanish Ministerio de Ciencia e Innovacion under Contracts No. FPA2007-66069 and No. FPA2009-13377-C02-02. Zs.D. acknowledgesthe financial support from OTKA Project No. K68801.