4 C ∗  ≤ ∑ i = 1... N   F u i  u i + 1       ≤ ∑ i = 1... N   F u i      ≤ ∑ i = 1... N   F i ∗          ( 9 )    MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=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@6583@