\(\newcommand{\im}{\operatorname{im}} \newcommand{\id}{\operatorname{id}} \newcommand{\orb}{\operatorname{orb}} \newcommand{\sgn}{\operatorname{sign}} \newcommand{\ff}{\mathbb{F}} \newcommand{\RR}{\mathbb{R}} \newcommand{\rr}{\mathbb{R}} \newcommand{\cc}{\mathbb{C}} \newcommand{\FF}{\mathbb{F}} \newcommand{\CC}{\mathbb{C}} \newcommand{\ZZ}{\mathbb{Z}} \newcommand{\zz}{\mathbb{Z}} \newcommand{\spa}{\operatorname{span}} \newcommand{\tr}{\operatorname{tr}} \newcommand{\rk}{\operatorname{rank}} \newcommand{\nul}{\operatorname{null}} \newcommand{\diag}{\operatorname{diag}}\)

References

Goldrei, DC. 2017. Classic Set Theory: For Guided Independent Study. Routledge.

Green, J.A. 1988. Sets and Groups : A First Course in Algebra. Library of Mathematics. Springer Netherlands.