eprintid: 10206634 rev_number: 7 eprint_status: archive userid: 699 dir: disk0/10/20/66/34 datestamp: 2025-03-28 09:22:15 lastmod: 2025-03-28 09:22:15 status_changed: 2025-03-28 09:22:15 type: article metadata_visibility: show sword_depositor: 699 creators_name: Fritz, Tobias creators_name: Gonda, Tomáš creators_name: Houghton-Larsen, Nicholas Gauguin creators_name: Lorenzin, Antonio creators_name: Perrone, Paolo creators_name: Stein, Dario title: Dilations and information flow axioms in categorical probability ispublished: pub divisions: UCL divisions: B04 divisions: F48 keywords: Categorical probability; Markov category; Semicartesian category; Information flow; Quasi-Borel space note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. abstract: We study the positivity and causality axioms for Markov categories as properties of dilations and information flow and also develop variations thereof for arbitrary semicartesian monoidal categories. These help us show that being a positive Markov category is merely an additional property of a symmetric monoidal category (rather than extra structure). We also characterize the positivity of representable Markov categories and prove that causality implies positivity, but not conversely. Finally, we note that positivity fails for quasi-Borel spaces and interpret this failure as a privacy property of probabilistic name generation. date: 2023-11 date_type: published publisher: Cambridge University Press official_url: https://doi.org/10.1017/s0960129523000324 oa_status: green full_text_type: other language: eng primo: open primo_central: open_green verified: verified_manual elements_id: 2357363 doi: 10.1017/S0960129523000324 lyricists_name: Lorenzin, Antonio lyricists_id: ALORE86 actors_name: Lorenzin, Antonio actors_id: ALORE86 actors_role: owner funding_acknowledgements: P 35992-N [Austrian Science Fund (FWF)]; Y 1261-N [START Prize of the Austrian Science Fund (FWF)]; [Sam Staton's grant BLaSt - a Better Language for Statistics of the European Research Council (ERC)] full_text_status: public publication: Mathematical Structures in Computer Science volume: 33 number: 10 pagerange: 913-957 pages: 45 issn: 0960-1295 citation: Fritz, Tobias; Gonda, Tomáš; Houghton-Larsen, Nicholas Gauguin; Lorenzin, Antonio; Perrone, Paolo; Stein, Dario; (2023) Dilations and information flow axioms in categorical probability. Mathematical Structures in Computer Science , 33 (10) pp. 913-957. 10.1017/S0960129523000324 <https://doi.org/10.1017/S0960129523000324>. Green open access document_url: https://discovery.ucl.ac.uk/id/eprint/10206634/1/Fritz%20Gonda%20Houghton-Larsen%20Lorenzin%20Perrone%20Stein%20-%20Dilations%20and%20information%20flow%20axioms%20in%20categorical%20probability.pdf