“…In order to predict links in hyper-relational KGs, pioneering works represent each hyperrelational fact as either an n-tuple in the form of r(e 1 , e 2 , • • • , e n ) (Wen et al, 2016;Zhang et al, 2018;Fatemi et al, 2020;Liu et al, 2020;Abboud et al, 2020) or a set of key-value pairs in the form of {(k i : v i )} m i=1 (Guan et al, 2019(Guan et al, , 2021Liu et al, 2021a). However, these modelings lose key structure information and are incompatible with the RDF-star schema (Arndt et al, 2021) used by modern KGs, where both primal triples and qualifiers constitute the fundamental data structure.…”