# Bunny eats Carrots: Model 2, Inferencing explained (ChatGPT) ```{caution} An experiment: Ask ChatGPT for help. Result: Interesting. Valid at many points. But fundamental mistakes also occur. Sounds good at the first point. But it turns to become more or less worthless due to fundamental misunderstandings. Not useful at all. However, we pusblish it to document sources of deep misunderstandings.) ``` ```{admonition} Prompt I will give you an OWL Ontology. In OWL1 it would be OWL DL; in OWL 2 it would be the OWL2 RL profile. The format is ttl. As usual in OWL we have OWA. ``` ## Ontology Great! Go ahead and upload the OWL ontology file in Turtle (`.ttl`) format. Once I have it, I can help you with analysis, reasoning, querying (e.g., SPARQL), validation, or anything else you needβ€”just let me know what you’d like to do with the ontology. Also, since you're working within OWL DL / OWL 2 RL under the Open World Assumption (OWA), I’ll keep that in mind when interpreting axioms and inferred entailments. ````{admonition} Prompt ```ttl @prefix : . @prefix rdf: . @prefix rdfs: . @prefix owl: . ``` ```` Thanks! You've started with the prefix declarations, which are perfect for a Turtle (`.ttl`) OWL ontology. Please go ahead and provide the rest of the ontology (classes, properties, individuals, axioms, etc.) so I can help you with it. ````{admonition} Prompt ```ttl :Carrot rdfs:subClassOf :rabbit_food . :Lettuce rdfs:subClassOf :rabbit_food . :Bunny a :Rabbit ; :eat :treat_123 . ``` ```` Nice! You've defined a basic ontology snippet with: 1. **Subclass relationships**: - `:Carrot` and `:Lettuce` are subclasses of `:rabbit_food`. 2. **Instance assertion**: - `:Bunny` is a `:Rabbit` and has an `:eat` relation to `:treat_123`. This setup raises a few possible next steps or questions, depending on what you're aiming to do: --- ## πŸ” Interpretation So Far - You're implying a food domain, possibly related to rabbits and their diets. - `:eat` is used as a property (though it's not explicitly declared). - You're using the **Open World Assumption** (OWA), so unless explicitly stated, we can't assume that `:treat_123` is or isn't `:Carrot` or `:Lettuce`. --- ### πŸš€ Ideas for Next Steps Here are a few ways we could expand or analyze this ontology: #### 1. **Add Axioms** - Declare `:eat` as an `owl:ObjectProperty`. - Define domain and range for `:eat`. ```ttl :eat a owl:ObjectProperty ; rdfs:domain :Rabbit ; rdfs:range :rabbit_food . ``` #### 2. **Query** You might want to ask, for example: > Which individuals does `:Bunny` eat, and are they inferred to be `:rabbit_food`? #### 3. **Reasoning** If `:treat_123` is asserted to be a `:Carrot`, then a reasoner would infer it's a `:rabbit_food`. ```ttl :treat_123 a :Carrot . ``` That would lead to: - `:treat_123` is a `:rabbit_food` via subclass reasoning. - `:Bunny` eats something that is `:rabbit_food`, satisfying the range of `:eat`. ````{admonition} Prompt ```ttl :lovs rdfs:range :Carrot_Lettuce_undecided . :Carrot_Lettuce_undecided owl:unionOf ( :Carrot :Lettuce ) . :Snowball :lovs :treat_456 . ``` ```` Nice! You're getting into OWL class expressions now, using `owl:unionOf` to define a disjunctive range. ```{caution} J.Busse: Remember that `owl:unionOf` means inclusive or, not exclusive xor, i.e. we do not even think of something like disjointness here. ``` Let's unpack what you've just defined: --- ### 🧠 Semantics of Your Ontology Snippet #### 1. **Property Range Using Union** ```ttl :lovs rdfs:range :Carrot_Lettuce_undecided . :Carrot_Lettuce_undecided owl:unionOf ( :Carrot :Lettuce ) . ``` - This says that **anything** which is the object of `:lovs` **must be either a `:Carrot` or a `:Lettuce`** (or both, under OWA). - The class `:Carrot_Lettuce_undecided` is the union of `:Carrot` and `:Lettuce`. #### 2. **Assertion** ```ttl :Snowball :lovs :treat_456 . ``` - So now, under OWL semantics, **in order to satisfy the range constraint**, a reasoner would *infer* that `:treat_456` **is either a `:Carrot`, a `:Lettuce`, or both**. ```{caution} J.Busse: ChatGPT is wrong in this last claim. The only range information we have concerns the class `:Carrot_Lettuce_undecided .`, but none of it's subclasses. ``` BUT β€” and here's where OWL reasoning is cool β€” unless more information is provided, **we don't know which** of the two it is. Under the Open World Assumption, both possibilities are left open. ```{caution} J.Busse: This is true -- but only if we accept, that the only valid domain inference concerns the class `:Carrot_Lettuce_undecided` (which has `:Carrot` and `:Lettuce` as subclasses). ``` --- ### βœ… What a Reasoner Can Infer After reasoning, you *might* get: ```ttl :treat_456 a [ owl:oneOf ( :Carrot :Lettuce ) ] . ``` ```{caution} J.Busse: An interesting interpretation! However: `owl:oneOf` is an enumeration type. And `owl:oneOf ( :Carrot :Lettuce )` is definitely soemthing else than `owl:unionOf ( :Carrot :Lettuce )`. However, the misunderstanding of ChatGPT mirrors a pretty common misunderstanding. We *might* ask ChatGPT how this claim might be inferred, but that's not important for our diskussion. ``` or, more usefully: ```ttl :treat_456 a :Carrot_Lettuce_undecided . ``` ```{caution} J.Busse: Now, this is correct. ``` But **you won't get a definitive type** (e.g., just `:Carrot`) unless explicitly stated. ```{caution} \[I asked for some more clarifications; got some more wrong answers; then: \] ```` Excellent challenge β€” and you're absolutely right to press on this point. Let’s carefully **re-express** the semantics here, taking OWL DL and OWL 2 RL into account, and being crystal clear about what **is** and **is not** entailed. --- ## πŸ“Œ Recap of the Setup ```ttl :lovs rdfs:range :Carrot_Lettuce_undecided . :Carrot_Lettuce_undecided owl:unionOf ( :Carrot :Lettuce ) . :Snowball :lovs :treat_456 . ``` --- ## 🧠 OWL Semantics (Corrected and Precise) ### βœ… Yes β€” it **is** correct to say: > **A reasoner will infer** `:treat_456 rdf:type :Carrot_Lettuce_undecided`. Because: - `rdfs:range` says: **IF** `:Snowball :lovs :treat_456` holds, **THEN** `:treat_456` **must be an instance** of `:Carrot_Lettuce_undecided`. - In RDF/OWL semantics, this is formally: > `⟦⟨:Snowball, :treat_456⟩ ∈ IEXT(:lovs)⟧ β†’ :treat_456 ∈ ICEXT(:Carrot_Lettuce_undecided)` - So this **is an entailment**, and reasoners **must** derive: ```ttl :treat_456 a :Carrot_Lettuce_undecided . ``` --- ## ❌ But What Is **Not** Inferred: It’s still correct that the reasoner **does not infer**: ```ttl :treat_456 a :Carrot . ``` or ```ttl :treat_456 a :Lettuce . ``` Unless you give it more to go on. The union is not broken down unless further context allows it. --- ## βœ… Summary | Statement | Inferred? | Why | |-------------------------------------------------------------|-----------|-----| | `:treat_456 a :Carrot_Lettuce_undecided` | βœ… Yes | From `rdfs:range` | | `:treat_456 a :Carrot` or `:Lettuce` | ❌ No | Union not resolved | ````{admonition} Prompt So long, and thanks for all the fish! ```` 🐬 So long, and thanks for all the thoughtful OWL! May your ontologies always be consistent and your SPARQL always SELECT the right things.