*Definition [#bc8b3a17]
-Let U be an initial universe set and E be a set of parameters. Let A ⊆ E. A pair (F, A) is called a soft set over U, where F is a mapping given by F : A → P(U). In other words, a soft set over U is a parametrized family of subsets of the universe U.

*Reference [#zc37678b]
-Molodtsov, D. ''Soft set theory -first results.'' (English summary), Global optimization, control, and games, III., Comput. Math. Appl. 37 (1999), no. 4-5, 19-31.