Convex AI Compositionality and the Governance of AI System Populations
Organizations: Institute of Biomedical Ethics and History of Medicine, University of Zürich, Zürich, Switzerland · SUPSI, Dalle Molle Institute for Artificial Intelligence (IDSIA), Lugano, Switzerland · ETH Zürich, Zürich, Switzerland
Abstract
AI governance increasingly requires providers and public authorities to reason about multiple AI instantiations, alternative versions, and deployment configurations of multiple AI systems. Yet current regulation remains predominantly single-system-centric, acknowledging such multiplicity only sparsely without treating collections of related AI systems as governance objects. This creates an AI population governance problem: determining which instantiations can be meaningfully considered together and how their changing configurations can be represented and monitored. The first requirement has recently been addressed through trustworthiness-based accounts of AI identity. We address the second by introducing convex AI compositionality: a formal representation of the configurations generated by finite AI system populations that uses convex spaces. The core idea is that convex compositions of the operational states that a population of AI system instantiations may occupy over time are compatible with lifecycle reachability across the population and can preserve the formal identity relations between these systems. Well-known statistical and geometric constructions, such as weighted state distributions and convex hulls, become AI governance tools for distinguishing operational states, population weights, heterogeneity, and AI configuration change across different governance modes while remaining compatible, under stated conditions, with lifecycle reachability and AI identity. We illustrate our AI population governance framework through distributed healthcare deployments and controlled deployment of recruitment AI variants.
Figures & tables
| Mode | Purpose | Evidence and anchors | Procedure | Signals and actions | Risks |
|---|---|---|---|---|---|
| Retrospective | Audit, incident analysis Reassessment | Archived states and weights Historical anchors | Reconstruct over time and anchor transformations in Trace state, weight, barycenter and variance changes | TW level transitions, heterogeneity changes Anchor occupancy drops to zero Incident audit or reassessment | Missing or changed records Selection or protocol bias |
| Operational | Lifecycle monitoring Post-market control | Current states and weights Occupied anchors and provenance | Update anchors, Track TW level and heterogeneity over time | Crossings, new states, weight shifts Review, restrict, or rollback | Noisy or delayed evidence Aggregate or anchor masking |
| Prospective | Pre-deployment scenarios Population update assessment | Evidence, constraints, assumptions Candidate or counterfactual anchors | Generate states and weights over time across scenarios Compare resulting and their metrics | Crossings or critical configurations Adapt or block deployment | Scenario misspecification Distribution shift |
Appendix figures & tables3 assets
Supplementary material from the paper’s appendix.
Appendix
| Symbol | Role in the formalization |
|---|---|
| Techno-function : the designed technical capability that fixes the AI system kind at the selected level of abstraction. | |
| Trustworthiness profile : the selected dimensions together with their requirements, measurement conventions, evidential conditions, normalization rules, and aggregation procedures. | |
| Quantified profile : a particular assessment produced under . Unlike , it varies across states, deployments, copies, variants, and times. | |
| Trustworthiness level function : the auditable rule assigning quantified profiles to a finite collection of governance-relevant levels ( Ferrario, 2026b ) . | |
| -relative state : the abstract state determined by a quantified profile and the level assigned to it. | |
| Primitive lifecycle vocabulary : the admissible elementary transformation types considered under the fixed datum , each represented by a relation on . |
| TW dimension | Representative evaluation measures / strategies | Representation in |
|---|---|---|
| Technical robustness & safety | Accuracy, AUROC Brier score, NLL, ECE Performance under distribution shift Certified accuracy Attack success and fooling rates OOD detection confidence scores | Higher-is-better performance measures are normalized directly; losses, errors, and attack rates are reversed. fixes the test population, shift/attack regime, and evaluation protocol. |
| Diversity, non-discrimination & fairness | Demographic/statistical parity difference Disparate impact Equal opportunity Equalized odds Predictive parity Generalized Entropy Index | Fairness measures are generally target-based. fixes protected groups, thresholds, targets, and the evaluation population. |
| Transparency & explainability | Faithfulness and fidelity Explanation robustness Sparsity and complexity Information loss and gain Human task accuracy Task time and satisfaction | Quantitative and human-evaluation measures are normalized according to their direction. Ordinal or subjective scales require a documented numerical encoding. |
| Privacy & data governance | -anonymity, -diversity, -closeness Differential-privacy Membership-inference attack success rate and TPR at low FPR Model-extraction fidelity/performance Model-inversion performance | fixes the privacy mechanism, threat model, and admissible ranges. Lower-is-better privacy-loss and attack measures are reversed. |
| Human agency & oversight | Human error rate Task-completion time Cognitive load Number of user actions Compliance rate Trust, reliance, and trust calibration User satisfaction | Performance and usability measures are oriented consistently; reliance and trust may require target-based or psychometric encoding. |
| Accountability & auditability | Attribution analysis Algorithmic auditing Legal and regulatory compliance assessment Remediation and redress evaluation Impact assessments | These are primarily qualitative, categorical, or procedural evaluations; few established quantitative metrics exist. Numerical inclusion in therefore requires an explicit operationalization. |
AI Governance
Artificial intelligence governance studies how laws, institutions, and technical controls shape AI development, deployment, accountability, and social effects.
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