Faculty of Computer Science

Research Group Theoretical Computer Science


Oberseminar: Heterogene formale Methoden


Date: 2020, December 1
Time: 09:00 a. m.
Place: Online
Author: Neuhaus, Fabian
Title: God, Aether, and the Election Fraud in Georgia

Abstract:

Classical logic assumes that all singular terms refer to exactly one entity in the domain of discourse. Gottlob Frege and Bertrand Russell, two of the founding fathers of symbolic logic, were quite aware that this assumption is problematic and may easily lead to nonsensical results. However, they struggled to find good solutions and, thus, the existential presupposition is part of classical first-order logic (FOL) and description logics.

This logical inheritance has a knock-on effect on knowledge representation languages like OWL. Because the existential presupposition entails that if we represent knowledge about some individual, then it must exist. E.g., if we were to create an OWL knowledge base about alleged irregularities during the last US election, then the mere mentioning of the dumpster full of Trump votes in Georgia would entail its existence.

“Free Logic” is a name for a variety of logical systems that remove the existential presupposition from classical logic. In the presentation I will discuss a joint paper with Guendalina Righetti and Oliver Kutz, where we propose 3 different free description logics. The presentation will cover the motivations for free logic, alternative design choices, how they are implemented, and the resulting differences between the logical systems.


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