Dedekind multisets and function shells
The author extends his axiomatization of multisets with finite multiplicities [Notre Dame J. Formal Logic 30, 36-66 (1989; Zbl 0668.03027)] to a corresponding theory for arbitrary multisets. Additionally, he describes an interpretation of this theory using function shells, i.e., suitable representatives of multisets within the ZF world.
scientific article; zbMATH DE number 179578