,
Callum Reader
Creative Commons Attribution 4.0 International license
In recent years a succession of papers have taken to representing string diagrams as hypergraphs, the advantage of which is that the structural equations of diagrams come for free from the hypergraph structure. This improves implementability and reduces the number of rewrites necessary for reasoning. Notably, however, string diagrams for compact closed categories have escaped this treatment. In this paper we introduce a combinatorial interpretation of compact closed string diagrams, via the Int construction on hypergraphs for traced string diagrams. Using this interpretation, we characterise string diagram rewriting as a suitable adaptation of double-pushout rewriting.
@InProceedings{digiorgio_et_al:LIPIcs.MFCS.2026.50,
author = {Di Giorgio, Alessandro and Reader, Callum},
title = {{Hypergraphs for Compact Closed Categories}},
booktitle = {51st International Symposium on Mathematical Foundations of Computer Science (MFCS 2026)},
pages = {50:1--50:16},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-442-0},
ISSN = {1868-8969},
year = {2026},
volume = {386},
editor = {Kouck\'{y}, Michal and Petrișan, Daniela},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2026.50},
URN = {urn:nbn:de:0030-drops-274318},
doi = {10.4230/LIPIcs.MFCS.2026.50},
annote = {Keywords: rewriting, compact closed categories, string diagrams}
}