In many applications of cooperative game theory -- from corporate governance and cartel formation to parliamentary voting -- not all winning coalitions are feasible. Ideological distances, institutional constraints, or pre-electoral agreements may render certain coalitions implausible. Classical power indices ignore this and weight all winning coalitions equally. We introduce cohesion structures to quantify coalition feasibility and axiomatically characterize two families of cohesion-sensitive power indices, represented as expected marginal contributions under Luce-type distributions. In the Banzhaf branch, coalition weights are a power transformation of cohesion; in the Shapley branch, additional axioms separate size from cohesion, recovering the classical size weights with cohesion acting within each size class. All results have been mechanically verified in Lean 4 with Mathlib. We illustrate the framework on the German Bundestag and the French Assemblée Nationale, where cordon sanitaire and double cordon scenarios produce sharp, interpretable power shifts.

翻译：在合作博弈论的众多应用中——从公司治理与卡特尔形成到议会投票——并非所有获胜联盟都是可行的。意识形态距离、制度约束或选举前协议可能使某些联盟缺乏可信性。经典权力指数忽略这一事实，对所有获胜联盟赋予同等权重。我们引入凝聚力结构来量化联盟的可行性，并公理化刻画了两个凝聚力敏感的权力指数族，这些指数表示为Luce型分布下的期望边际贡献。在Banzhaf分支中，联盟权重是凝聚力的幂变换；在Shapley分支中，附加公理将规模与凝聚力分离，在保持每个规模等级内部凝聚力作用的同时，恢复了经典的规模权重。所有结果已通过Lean 4与Mathlib库进行了机械化验证。我们以德国联邦议院和法国国民议会为例说明该框架，其中防疫线及双重防疫线场景产生了清晰且可解释的权力转移。