Reigning spiders

Created in December 01, 2022

2022   ·   ontology   ssw

Originally posted as part of the CMPE58H course by Susan Üsküdarlı in the fall semester of 2022 at https://furkanakkurt5204.gitlab.io/personal/ontology/2022/12/01/reigning-spiders.

I wondered about reasoners. W3C has the Semantic Web Rule Language (SWRL). Its syntax is similar to a notation I learned during CMPE260: Extended Backus–Naur form (EBNF). They define rules as axioms: axiom ::= rule.

The axioms have antecedents (body) and consequents (head), each composed of atoms. The rule may be defined as: if antecedent, then consequent. Basic atoms are of the forms:

  1. C(x): descriptions
    • Example: ontolex:LexicalConcept(:hebûn_v_ku_sense_concept)
  2. P(x, y): relations
    • Example: skos:definition(:hebûn_v_en_sense_concept, "assets"@en)
  3. sameAs(x, y): equalization
    • Example: sameAs(foaf:Person, wd:Q5)

Compositing atoms, one can construct very complex rules. One such rule would be, informally: parent(?x, ?y) ∧ parent(?y, ?z) ⇒ grandparent(?x, ?z).

Sidenote: In the specification, they mention that sameAs and differentFrom atoms do not increase the expressivity of the language since OWL and rules together without these atoms are capable of the same expressions.