ADDITIVE‐INTERACTION MODELS OF SPATIAL AGGLOMERATION*
通过数学等价性统一了多种空间集聚模型，利用凸函数的共轭理论揭示了空间可达性、内生接触和固定接触三类模型之间的对称对应关系，有助于模型间的结果转移和新经济解释。
ABSTRACT A wide variety of existing models of spatial agglomeration postulate additive‐interaction effects among agents. In this paper, a synthesis of such models is achieved by establishing certain mathematical equivalences between them. In particular, it is shown that Rockafellar's conjugacy theory of concave functions yields a symmetric one‐to‐one correspondence between three classes of existing models, here designated as spatial‐accessibility models, endogenous‐contact models, and fixed‐contact models. These correspondences not only allow the transference of results between models, but also suggest new economic interpretations of each model in terms of its conjugate model. A series of examples are drawn from the literature to illustrate these results.