F z  < 2 × C ∗  − ∑ i ≠ k   F i ∗    ,       ( 3 )    MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaacqWGgbGrdaWgaaWcbaGaemOEaOhabeaakiabgYda8iabikdaYiabgEna0kabdoeadnaaCaaaleqabaGaey4fIOcaaOGaeyOeI0YaaabuaeaacqWGgbGrdaqhaaWcbaGaemyAaKgabaGaey4fIOcaaaqaaiabdMgaPjabgcMi5kabdUgaRbqab0GaeyyeIuoakiabcYcaSiaaxMaacaWLjaWaaeWaceaacqaIZaWmaiaawIcacaGLPaaaaaa@4575@