M ( a b , c d )  Π ( a , b ) Π ( c , d )   ≃ ( n − r − 1 ) ( n − r − 2 ) μ ( a ) μ ( c )   + ∑ δ = 1  r − 1   ( n − δ − 2 ) ( μ ( c ) Π δ  ( d , a ) + μ ( a ) Π δ  ( b , c )  )        ( 63 )       MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=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@8F7D@