,
Titouan Carette
,
Cole Comfort
Creative Commons Attribution 4.0 International license
We introduce a family of diagrammatical equational theories unifying two research programs: categorical quantum mechanics and graphical linear algebra. We prove their completeness with respect to denotational semantics described in terms of relations between vector spaces equipped with symplectic structure. This provides versatile graphical languages encompassing both affinely constrained classical mechanical systems, as well as odd-prime-dimensional stabiliser and Gaussian quantum circuits. Terms are described by labelled graphs with input and output interfaces, and the languages are equipped with equational theories amenable to standard graph rewriting techniques. In order to reason about large composite systems, we introduce a compact scalable notation where the vertices are themselves labelled by graphs. This notation allows us to state new and powerful rewrite rules which operate on diagrams at a large scale. We also show how this notation neatly captures some important constructions, such as graph states of quantum computing and the impedance and admittance matrices of electrical networks.
@InProceedings{booth_et_al:LIPIcs.FSCD.2026.7,
author = {Booth, Robert I. and Carette, Titouan and Comfort, Cole},
title = {{Graphical Symplectic Algebra}},
booktitle = {11th International Conference on Formal Structures for Computation and Deduction (FSCD 2026)},
pages = {7:1--7:22},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-433-8},
ISSN = {1868-8969},
year = {2026},
volume = {378},
editor = {Pfenning, Frank},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2026.7},
URN = {urn:nbn:de:0030-drops-263573},
doi = {10.4230/LIPIcs.FSCD.2026.7},
annote = {Keywords: graphical algebra, symplectic geometry, string diagrams, category theory, classical mechanics, quantum mechanics, graph theory}
}