Value Coalition Logic: A Typed Assignment-Based Reconstruction of Coalition Logic

2026-05-25Logic in Computer Science

Logic in Computer Science
AI summary

The authors propose Value Coalition Logic, which keeps the usual idea of coalitions working together but changes how basic facts are represented. Instead of just true or false statements, states assign specific values to typed variables, making the logic more structured and consistent internally. They show that this new logic matches classical coalition logic when looking at coherent valuations, leading to a complete set of rules for reasoning. Their main contribution is revealing new structural properties about coalitions and their abilities by focusing on value assignments rather than flat propositions.

Coalition LogicStrategic SemanticsTyped VariablesGame FormsAxiomatisationEffectivity FamiliesHypergraphsValue AssignmentsMutual ExclusionTruth-Equivalence
Authors
Shanxia Wang
Abstract
We introduce Value Coalition Logic, a typed assignment-based reconstruction of classical coalition logic. The strategic semantics is unchanged: coalitional ability is still interpreted by the standard one-step game-form clause. The change is at the atomic level. Instead of flat propositional valuations, states carry total assignments of values to finitely typed variables. As a result, exhaustivity and mutual exclusion of alternative values are built into the semantics, rather than imposed as external coherence constraints. We prove that, over each fixed finite typed signature, Value Coalition Logic is truth-equivalent to propositional coalition logic over coherent valuations. This correspondence yields a sound and complete Hilbert-style axiomatisation obtained by adding finite-domain value-coherence axioms to the standard axioms of coalition logic. The main contribution is structural. Projecting ordinary coalitional ability onto a single value domain yields quotient game forms, projected effectivity families, and strategic value-range hypergraphs. These structures support set-valued strategic exclusion, transversal polarity for disjoint coalitions, exact boundary duality between the empty and grand coalitions, and a measure of residual value indeterminacy. Thus the logic is conservative in its strategic modality, but exposes value-level invariants that are hidden in flat propositional encodings.