Biprofile Deviation Logic: Report-Replacement Frames and Audit Witnesses
This work provides a formal logical framework for auditing strategic behavior in social choice, but the contribution is primarily theoretical and incremental, building on existing logical and social choice foundations.
The paper introduces biprofile deviation logic to model strategic social choice, proving soundness and completeness for abstract frames, and providing audit mechanisms for representation changes such as manipulation witnesses and off-domain extensions.
Biprofile deviation logic models strategic social choice states as pairs $(R,P)$, where $R$ is the true profile used for welfare comparisons and $P$ is the submitted report profile used by the rule. Coalition modalities replace only the reports of the coalition, and their relations satisfy the fixed law $E_C \circ E_D = E_{C \cup D}$. The paper proves soundness and completeness of $H_{\mathrm{bp}}$ for the abstract frame class $\mathrm{Dev}(N)$, with the reverse-composition midpoint displayed inside the canonical proof. It then separates abstract $\mathrm{Dev}(N)$-components from genuine report-coordinate products by coordinate separation. On the social-choice side, the classical facts supply the source notions; the paper-specific contribution is the audit layer for representation changes: typed manipulation witnesses, a boundary-row theorem for off-domain extensions, and a factor-closure criterion for public deletions. The ancillary material contains the input formats, an executable certificate checker, Lean and Alloy companions for the finite relational lemmas and update patterns, recorded run logs, and checksums.