Аннотация:The paper studies complementary choice functions, i.e. monotonic and consistent choice functions. Such choice functions were introduced and used in the work [13] for investigation of matchings with complementary contracts. We provide three (universal) ways of constructing such choice functions: through pre-topologies, as direct images of completely
complementary (or pre-ordered) choice functions, and with the help of supermodular setfunctions.
Keywords Choice function · Substitute · Pre-topology · Pre-order · Supermodularity · Lattice