170 lines
6.3 KiB
Markdown
170 lines
6.3 KiB
Markdown
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---
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title: RDF Schema
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TARGET DECK: Obsidian::STEM
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FILE TAGS: data_model::rdf::schema
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tags:
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- rdf
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---
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## Overview
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The simplest extension to RDF that allows a modeler to manage inference is **RDF Schema** (RDFS).
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%%ANKI
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Basic
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What is considered the simplest extension to RDF that enables inference?
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Back: RDFS.
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Reference: Allemang, Dean, James A. Hendler, and Fabien L. Gandon. _Semantic Web for the Working Ontologist_. 3e ed. ACM Books 33. New York: Association for computing machinery, 2020.
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<!--ID: 1736629473650-->
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END%%
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%%ANKI
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Basic
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What is RDFS an acronym for?
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Back: **R**esource **D**escription **F**ramework **S**chema.
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Reference: Allemang, Dean, James A. Hendler, and Fabien L. Gandon. _Semantic Web for the Working Ontologist_. 3e ed. ACM Books 33. New York: Association for computing machinery, 2020.
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<!--ID: 1736629473653-->
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END%%
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## Classes
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All things described by RDF are called **resources**. Resources may be divided into groups called **classes**. Classes are themselves resources. The `rdf:type` property may be used to state that a resource is an instance of a class. Associated with a class is a set, called the **class extension** of the class, which is the set of the instances of the class. A class may be a member of its own class extension.
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The group of resources that are RDFS classes is itself a class called `rdfs:Class`. The `rdfs:Resource` class is the class of everything.
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If a class `C` is a subclass of a class `C'`, then all instances of `C` will also be instances of `C'`. The `rdfs:subClassOf` property may be used to state that one class is a subclass of another.
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%%ANKI
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Basic
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What is a resource?
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Back: Anything described by RDF.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473656-->
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END%%
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%%ANKI
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Cloze
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{Resources} may be divided into groups called {classes}.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473659-->
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END%%
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%%ANKI
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Basic
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Is every resource a class?
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Back: No.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473661-->
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END%%
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%%ANKI
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Basic
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Is every class a resource?
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Back: Yes.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473664-->
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END%%
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%%ANKI
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Cloze
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The {`rdf:type`} property states {a resource is an instance of a class}.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473667-->
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END%%
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%%ANKI
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Cloze
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The {`rdfs:subClassOf`} property states {a class is a subclass of another}.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473670-->
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END%%
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%%ANKI
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Basic
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Which property describes "`?A` is an instance of `?B`"?
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Back: `rdf:type`
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473672-->
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END%%
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%%ANKI
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Basic
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Which property describes "`?A`'s class extension is a subset of `?B`'s"?
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Back: `rdfs:subClassOf`
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473675-->
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END%%
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%%ANKI
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Basic
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*What* is the class extension of a class?
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Back: The collection of instances of the class.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473678-->
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END%%
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%%ANKI
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Basic
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Which class is the class of everything?
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Back: `rdfs:Resource`
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473681-->
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END%%
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%%ANKI
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Basic
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What does the `rdfs:Resource` class describe?
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Back: Any RDF resource.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473685-->
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END%%
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%%ANKI
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Basic
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What is the class extension of `rdfs:Resource`?
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Back: Every resource.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473688-->
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END%%
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%%ANKI
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Cloze
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The meaning of the {`rdfs:subClassOf`} property is given by the {type propagation} rule.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473691-->
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END%%
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%%ANKI
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Basic
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Which two properties make up the type propagation rule?
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Back: `rdf:type` and `rdfs:subClassOf`.
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Reference: “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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<!--ID: 1736629473694-->
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END%%
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%%ANKI
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Cloze
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The type propagation rule states:
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* if {`?A rdfs:subClassOf ?B`}
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* and {`?x rdf:type ?A`}
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* then {`?x rdf:type ?B`}.
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Reference: Allemang, Dean, James A. Hendler, and Fabien L. Gandon. _Semantic Web for the Working Ontologist_. 3e ed. ACM Books 33. New York: Association for computing machinery, 2020.
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<!--ID: 1736629473698-->
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END%%
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%%ANKI
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Basic
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How is the type propagation rule stated in SPARQL?
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Back:
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```sparql
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CONSTRUCT { ?x rdf:type ?B }
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WHERE { ?A rdf:subClassOf ?B. ?x rdf:type ?A }
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```
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Reference: Allemang, Dean, James A. Hendler, and Fabien L. Gandon. _Semantic Web for the Working Ontologist_. 3e ed. ACM Books 33. New York: Association for computing machinery, 2020.
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<!--ID: 1736629473701-->
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END%%
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## Bibliography
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* Allemang, Dean, James A. Hendler, and Fabien L. Gandon. _Semantic Web for the Working Ontologist_. 3e ed. ACM Books 33. New York: Association for computing machinery, 2020.
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* “RDF 1.2 Schema,” accessed January 11, 2025, [https://www.w3.org/TR/rdf12-schema/#ch_class](https://www.w3.org/TR/rdf12-schema/#ch_class).
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