$$ \def\R{\mathbb R} \def\N{\mathbb N} \def\Q{\mathbb Q} \def\Z{\mathbb Z} \newcommand{\st}{~:~} \newcommand{\cee}{\mathsf{C}} \newcommand{\bee}{\mathrm{B}} \def\mathhlyellow#1{\bbox[##fff3bf,2px,border:1px solid ##b7791f]{#1}} \def\mathhlgold#1{\bbox[##ffe8a3,2px,border:1px solid ##b7791f]{#1}} \def\mathhlorange#1{\bbox[##ffddb3,2px,border:1px solid ##c05621]{#1}} \def\mathhlgreen#1{\bbox[##d9f7d7,2px,border:1px solid ##3f8f46]{#1}} \def\mathhlmint#1{\bbox[##d4f5e9,2px,border:1px solid ##2c7a7b]{#1}} \def\mathhlblue#1{\bbox[##dceeff,2px,border:1px solid ##2b6cb0]{#1}} \def\mathhlpurple#1{\bbox[##eadffd,2px,border:1px solid ##6b46c1]{#1}} \def\mathhlpink#1{\bbox[##ffdbe8,2px,border:1px solid ##b83280]{#1}} \def\mathhlred#1{\bbox[##ffd6d6,2px,border:1px solid ##c53030]{#1}} \def\mathhlgray#1{\bbox[##e8ecef,2px,border:1px solid ##64748b]{#1}} \def\mathhlgrey#1{\bbox[##e8ecef,2px,border:1px solid ##64748b]{#1}} $$

References

Abbott, Stephen. 2016. Understanding Analysis. Vol. 2. Springer.
Rock, John A. 2025. Arbitrarily Close. 619 Wreath.
Schumacher, Carol. 2008. Closer and Closer: Introducing Real Analysis. Jones and Bartlett Publishers.