Fixpoint Semantics for Recursive SHACL

Bart Bogaerts, Maxime Jakubowski

Research output: Chapter in Book/Report/Conference proceedingConference paper

1 Downloads (Pure)


SHACL is a W3C-proposed language for expressing structural constraints on RDF graphs. The recommendation only specifies semantics for non-recursive SHACL; recently, some efforts have been made to allow recursive SHACL schemas. In this paper, we argue that for defining and studying semantics of recursive SHACL, lessons can be learned from years of research in non-monotonic reasoning. We show that from a SHACL schema, a three-valued semantic operator can directly be obtained. Building on Approximation Fixpoint Theory (AFT), this operator immediately induces a wide variety of semantics, including a supported, stable, and well-founded semantics, related in the expected ways. By building on AFT, a rich body of theoretical results becomes directly available for SHACL. As such, the main contribution of this short paper is providing theoretical foundations for the study of recursive SHACL, which can later enable an informed decision for an extension of the W3C recommendation.

Original languageEnglish
Title of host publicationProceedings 37th International Conference on Logic Programming (Technical Communications)
PublisherOpen Publishing Association
Number of pages7
Publication statusPublished - 17 Sep 2021
Event37th International Conference on Logic Programming - Porto, Porto, Portugal
Duration: 20 Sep 202127 Sep 2021
Conference number: 37

Publication series

NameElectronic Proceedings in Computer Science
PublisherOpen Publishing Association
ISSN (Print)2075-2180
ISSN (Electronic)2075-2180


Conference37th International Conference on Logic Programming
Abbreviated titleICLP


Dive into the research topics of 'Fixpoint Semantics for Recursive SHACL'. Together they form a unique fingerprint.

Cite this