Assortative Matching and Search
在Becker（1973）的新古典婚姻市场模型中引入时间密集的伴侣搜索和可转移产出，证明存在连续类型的搜索均衡，并发现仅靠产出的超模性不足以保证分类匹配，需附加log f的超模性等条件。
In Becker's (1973) neoclassical marriage market model, matching is positively assortative if types are complements: i.e., match output f(x, y) is suipermoddlar in x and y. We reprise this famous result assuming time-intensive partner search and transferable output. We prove existence of a search equilibrium with a continuum of types, and then characterize matching. After showing that Becker's conditions on match output no longer suffice for assortative matching, we find sufficient conditions valid for any search frictions and type distribution: supermodularity not only of output f, but also of log f, and log f Symmetric submodularity conditions imply negatively assortative matching. Examples show these conditions are necessary.