eprintid: 10134566 rev_number: 15 eprint_status: archive userid: 608 dir: disk0/10/13/45/66 datestamp: 2021-09-17 10:54:10 lastmod: 2022-03-22 07:10:19 status_changed: 2021-09-17 10:54:10 type: article metadata_visibility: show creators_name: Hirsch, R creators_name: Stokes, T title: Axioms for signatures with domain and demonic composition ispublished: pub divisions: UCL divisions: B04 divisions: C05 divisions: F48 keywords: Demonic composition, demonic refinement, binary relation, non-deterministic program, total correctness, axiomatisation. note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: Demonic composition ∗ is an associative operation on binary relations, and demonic refinement ⊑ is a partial order on binary relations. Other operations on binary relations considered here include the unary domain operation D and the left restrictive multiplication operation ∘ given by s∘t=D(s)∗t. We show that the class of relation algebras of signature {⊑,D,∗}, or equivalently {⊆,∘,∗}, has no finite axiomatisation. A large number of other non-finite axiomatisability consequences of this result are also given, along with some further negative results for related signatures. On the positive side, a finite set of axioms is obtained for relation algebras with signature {⊑,∘,∗}, hence also for {⊆,∘,∗}. date: 2021-05 date_type: published publisher: SPRINGER BASEL AG official_url: https://doi.org/10.1007/s00012-021-00719-4 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 1855742 doi: 10.1007/s00012-021-00719-4 lyricists_name: Hirsch, Robin lyricists_id: RHIRS08 actors_name: Hirsch, Robin actors_id: RHIRS08 actors_role: owner full_text_status: public publication: Algebra universalis volume: 82 number: 2 article_number: 24 pages: 19 citation: Hirsch, R; Stokes, T; (2021) Axioms for signatures with domain and demonic composition. Algebra universalis , 82 (2) , Article 24. 10.1007/s00012-021-00719-4 <https://doi.org/10.1007/s00012-021-00719-4>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10134566/1/demonic-revised-post-review.pdf