Computable definitions allow automated reasoners to infer new relationships. (a) Before reasoning, the class "helper T cell" on the right of the graph has no is_a sub-types. (b) Representation of the same entities after reasoning over the ontology. "Helper T cell" has numerous implied is_a sub-types based on its computable definition "helper T cell is_a T cell capable_of cytokine secretion".
Meehan et al. BMC Bioinformatics 2011 12:6 doi:10.1186/1471-2105-12-6