Relationships and events: a general theory of reification and truthmaking

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Language: English

Reification is a standard technique in conceptual modeling and knowledge representation. Classic examples are the reification of relationships and events. But how to decide what should be reified? Recent work on formal ontology offers us a simple answer: put in the domain of discourse those entities that are responsible for the truth of our propositions. These are called truthmakers. In the recent years, with Giancarlo Guizzardi and Daniele Porello we have developed a novel theory of relations and relationships based on a re-visitation of Guizzardi’s relators that builds on the ontological notion of truthmaking. In this tutorial I will illustrate this theory in some detail, presenting several modeling patterns that account for the different ways relationships and events can be considered as truthmakers, and showing how most relationships can be seen as the focus of events, which emerge from the context (the scene) they occur in.


Guarino, N., & Guizzardi, G. (2015). We need to discuss the relationship: Re-visiting relationships as modeling constructs. In International conference on advanced information systems engineering, caise 2015 (pp. 279–294).

Guarino, N., & Guizzardi, G. (2016). Relationships and events: Towards a general theory of reification and truthmaking. In AI*IA 2016: Advances in artificial intelligence, Genova, Italy, November 29 – December 1, 2016 (pp. 237–249).

Guarino, N., Sales, T. P., & Guizzardi, G. (2018). Reification and truthmaking patterns. In Conceptual modeling – 37th international conference, ER 2018, Xi’an, China, October 22-25, 2018. (pp. 151–165).


Events and their context

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Language: English

About the speaker

Nicola Guarino works at the Institute of Cognitive Sciences and Technologies of the Italian National Research Council, leading the Laboratory for Applied Ontology (LOA) located in Trento. A graduate in electronics engineering at Padua university in 1978, since 1991 has been playing a leading role in the ontology field, developing a strongly interdisciplinary approach that combines together Computer Science, Philosophy, and Linguistics. Among the most well known results of his lab, the OntoClean methodology and the DOLCE foundational ontology. He is founder and former editor-in-chief of the Applied Ontology journal, founder and past president of the International Association for Ontology and its Applications (IAOA), former general chair of the international conference on Formal Ontology in Information Systems (FOIS), and editorial board member of Journal of Data Semantics.