A knowledge graph is mathematically defined as mathcal{G} = {mathcal{E}, mathcal{R}, mathcal{F}}, where $\mathcal{E}$ is a set of entities, $\mathcal{R}$ is a set of relations, and $\mathcal{F}$ is a set of facts. A fact is denoted as a triple (h, r, t), with $h$ being the head entity, $r$ the relation, and $t$ the tail entity.