# Quotation in Formal Logics and the Web

##### Lehrveranstaltung mit SWS 2/2/0 (Vorlesung/Übung/Praktikum) in SS 2023

Dozent

Umfang (SWS)

• 2/2/0

Module

Leistungskontrolle

• Mündliche Prüfung

When formalising knowledge in order to process it with the computer and to reason upon it, we often encounter situations in which people make statements about statements or in which they talk about a term instead of its meaning. As an illustration consider the following sentences:

```       Alice is a girl.
Alice has 5 letters.
Bob says that Alice is a girl.
```

The second and the third sentence are examples of quotations. “Alice” as present in the first sentence refers to a different object than “Alice” in the second sentence. The third sentence somehow refers to the first one and it depends on the intended use of the third sentence how this “somehow” can be further specified.

That quotation is not only of theoretical relevance but also interesting in practice can for example be observed in the Semantic Web where the standard Resource Description Framework (RDF) is currently extended by the opportunity to make statements about statements. The semantics of this extension, called RDF-star, will also depend on the industrial use cases this form of quotation is supposed to solve.

In this lecture, we will closely follow the standardisation progress of RDF-star and the different possible ways to define its semantics. Additionally, we will also take a broader look at the handling of quotation in other logical frameworks such as first order logic, common logic and modal logic.

The lecture and exercises are planned as a mixture of introductory lectures, discussions about different research approaches, and a few practical lessons implementing some of the proposals.

The lectures will take place on Tuesdays, 2. DS in MER/0003/U, exercises Wednesdays, 3. DS in BAR/0I89/U.

The first lecture will be on the 18th of April.

First-Order Logic and use mention:

• Ebbinghaus, Heinz-Dieter, et al. Mathematical logic. Vol. 1910. New York: Springer, 1994.
• Pardey, Ulrich, and Kai F. Wehmeier. "Frege’s Begriffsschrift theory of identity vindicated." Oxford studies in philosophy of language 1 (2019): 122-147.

Semantic Web in general:

• Hitzler, Pascal, Markus Krotzsch, and Sebastian Rudolph. Foundations of semantic web technologies. CRC press, 2009.

RDF-star:

Named graphs:

(more references will be added during the course)
 Vorlesung Introduction DS2, 18. April 2023 in MER/0003/U Übung Logical Background DS3, 19. April 2023 in BAR/0I89/U Vorlesung First Order Logic DS2, 25. April 2023 in MER/0003/U Übung Exercise: First Order Logic DS3, 26. April 2023 in BAR/0I89/U Vorlesung Frege and the use-mention problem DS2, 2. Mai 2023 in MER/0003/U Übung Exercise: Use-mention DS3, 3. Mai 2023 in BAR/0I89/U Vorlesung Semantic Web and RDF DS2, 9. Mai 2023 in MER/0003/U Entfällt Dies Academicus DS3, 10. Mai 2023 in BAR/0I89/U Vorlesung RDF reification and use cases DS2, 16. Mai 2023 in MER/0003/U Übung Exercise: use cases DS3, 17. Mai 2023 in BAR/0I89/U Vorlesung RDF-star DS2, 23. Mai 2023 in MER/0003/U Übung Exercise/discussion: current state of RDF-star DS3, 24. Mai 2023 in BAR/0I89/U Vorlesung RDF: Singleton properties DS2, 6. Juni 2023 in MER/0003/U Übung Exercise/Discussion: Singleton properties DS3, 7. Juni 2023 in BAR/0I89/U Vorlesung RDF: Named Graphs DS2, 13. Juni 2023 in MER/0003/U Übung Exercise: Rules for named graphs semantics DS3, 14. Juni 2023 in BAR/0I89/U Vorlesung Notation3 Logic DS2, 20. Juni 2023 in MER/0003/U Übung Exercise: Notation3 Logic DS3, 21. Juni 2023 in BAR/0I89/U Vorlesung ISO Common Logic DS2, 27. Juni 2023 in MER/0003/U Übung Exercise: Common Logic DS3, 28. Juni 2023 in BAR/0I89/U Vorlesung Modal Logic DS2, 4. Juli 2023 in MER/0003/U Übung Exercise/Discussion: Modal Logic and Web use cases DS3, 5. Juli 2023 in BAR/0I89/U Vorlesung Summary and Update on RDF-star DS2, 11. Juli 2023 in MER/0003/U Übung Open exercise session (if needed) DS3, 12. Juli 2023 in BAR/0I89/U