Results on strategic complementarities provide a productive method of structuring
problems in which we make several policy choices simultaneously. If two policy choices
are strategic complements, then monotone comparative statics are guaranteed. If the policy
choices are not strategic complements, then the theory either must impose restrictions on
the magnitude of the coefficients or it must be tested using a system of simultaneous
equations.

the theoretical requirements for monotone comparative statics are the single-crossing property and quasi-supermodularity.

有谁能简单的说一下这两个条件及其与monotone comparative statics 的关系。谢谢了