setbuilder

Version 0.2.0 (2026-07-28)

Smart set-builder notation for LaTeX: one command instead of \left\{ ... \,\middle\vert\, ... \right\}.

\usepackage{setbuilder}
...
\set{x \in \mathbb{R} \given x^2 < 2}      % { x ∈ ℝ | x² < 2 }
\set*{\frac{n}{n+1} \given n \in \mathbb{N}}   % braces AND bar auto-scale
\set[\Big]{x \given f(x) = \max_y f(y)}    % fixed size

Features:

• correct thin spaces around the separator, which automatically vanish in sub/superscripts (\nonscript);
• a thin space just inside the braces — but only for a set given by a condition, { x | x > 0 }, never for a plain enumeration, {1, 2, 3} (Knuth, TeXbook);
• the separator bar scales together with the braces in the starred and sized forms;
• line breaks are permitted after the bar in inline formulas;
• \suchthat as a synonym of \given; both give a descriptive error when used outside \set.

Options

Option	Effect
bar (default)	separator is a vertical bar: { x | x > 0 }
colon	separator is a colon: { x : x > 0 }
pad=<mu glue>	space inside the braces, default \,; pad=none disables it
synonym=<name>	additionally define \<name> as a full copy of \set

If another package already defines \set, setbuilder leaves it untouched and recommends choosing a synonym:

\usepackage[synonym=mkset]{setbuilder}

Installation

Once on CTAN, the package is available in TeX Live and MiKTeX: tlmgr install setbuilder. For manual installation, copy setbuilder.sty into your project directory or into your personal TeX tree (~/texmf/tex/latex/setbuilder/).

Requirements

• mathtools
• LaTeX kernel 2022-06-01 or newer (key-value options, \NewCommandCopy)

Documentation

See setbuilder.pdf for the full manual with typeset examples.

Author

Vseslav Sekorin vssekorin@gmail.com

License

Copyright (c) 2026 Vseslav Sekorin. This material is subject to the MIT License; see the LICENSE file for the full text.