The revised IPF. In addition to the K1 IPF (thick solid curve), two possible IPF forms are displayed. These are identified as solutions in Figs. 5 and 7, and are shown as the thin solid line (K-type, Eq. (4) with the asymptotic solution δ = 29.52   η;η = 18.7 and f_pms = 1.0) and the thick dashed line (DM-type, Eq. (6) with σlP = 2.3,avlP = 5.0,f_ms = 1.0). The thin dashed line is the DM PDPF. Data points with observational error bars are as indicated in the key. These are used to test hypothesis 5 and 6 giving (thin solid curve), (thick dashed curve) and (thick solid curve).