1. Son of SN Barry Smith

2. The Virtues of Single Inheritance (= True Hierarchy) better coding clearer instructions better automatic reasoning better definitions

3. 3 Better coding: Shortfalls from single inheritance are often clues to bad coding, since they mark deviations from is_a relations which also block ontology alignment e.g. because is_a is no longer transitive because is_a is allowed to mean several different things Cf. Gene Ontology

4. Use of multiple inheritance involves the assignment to the is_a relation of a plurality of different meanings within a single ontology. The resultant mélange makes coherent integration across ontologies achievable (at best) only under the guidance of human beings with relevant biological knowledge

5. Is_a Overloading The success of ontology alignment depends crucially on the degree to which basic ontological relations such as is a can be relied on as having the same meanings in the different ontologies to be aligned.

6. SN is not really a hierarchy because SN’s is_a tail, the Metathesaurus, brings multiple inheritance e.g. regarding every chemical in Meta is_a chemical viewed structurally and is_a chemical viewed functionally

7. Here again: the presence of such Meta-induced multiple inheritance is a clue to potential coding errors/suspicious terms in the SN: e.g. Finding Environmental Effect of Humans

8. Better definitions No circularity – therefore declare primitives Necessary and sufficient conditions (definitions should have the form: x is an instance of A =def x is an instance of [A’s parent term, the genus] which B [the differentia] Intelligibility Substitutability

9. UMLS-SN Semantic Relations Semantic Relation: developmental_form_of TUI: T179 Definition: An earlier stage in the individual maturation of. satisfies substitutability

10. UMLS-SN Semantic Relations Semantic Relation: causes TUI: T147 Definition: Brings about a condition or an effect.

11. Olivier’s goals Semantic types 1.rename some types 2.extract explicit classificatory principles 3.rearrange hierarchy as needed 4.revisit roles (place under sortals when unique)