(Bordes et al., 2013a;Bordes et al., 2013b) that most of the relation instances in the knowledge graph are hierarchical and irreflexive.
the relationship of each triplet (h, r, t) can be regarded as a directed transition r in the embedding space from the head entity h to the tail entity t. Ideally, if all the correct triplets follow the assumption that every relation instance is strictly single-mapping (i.e.