 (in which case, again, Transitivity and Supplementation would suffice, i.e., GEM = (P.2) + (P.4) + (P.151) + (P.17)). For other ways of axiomatizatizing of GEM using (P.151), see e.g. Link (1983) and Landman (1991) (and, again, Hovda 2009). See also Sharvy (1980, 1983), where the extension of M obtained by adding (P.151) is called a “quasi-mereology”. 