Consider two non-inbred relatives i and j with parents k and l and m and n, respectively. Show that

∆7 = ΦkmΦln + ΦknΦlm

∆8 = 4Φij − 2∆7

∆9 = 1 − ∆7 − ∆8, where the condensed identity coefficients all pertain to the pair i and j. Thus, in the absence of inbreeding, all nonzero condensed identity coefficients can be expressed in terms of ordinary kinship coefficients.