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Scissor LaTeX

bm (bold math) in Scissor LaTeX

The bm package works in Scissor LaTeX: \bm{...} makes Latin letters, Greek letters and symbols such as \nabla bold, and \boldsymbol from amsmath does the same.

What the package does

bm gives you \bm{...}, which sets its argument in bold while keeping the math style. Letters stay italic, so \bm{x} is a bold italic x, and Greek letters and symbols become bold too. \mathbf{x} instead gives an upright bold x and leaves Greek lower-case letters unchanged in a TeX installation.

What works here

CommandIn Scissor LaTeXNotes
\bm{x}, \bm{A}WorksBold italic letters.
\bm{\alpha}, \bm{\Sigma}, \bm{\mu}WorksBold Greek letters.
\bm{\nabla}, \bm{1}WorksBold symbols and digits.
\boldsymbol{...} (amsmath)WorksSame result as \bm.
\mathbf{x}WorksUpright bold.

Examples

Vectors and matrices in a linear system:

Bold vectors and matrices

LaTeXPreamble: \usepackage{bm}Open in editor
\bm{A}\bm{x} = \bm{b},
\qquad
\bm{x} = (x_1, \dots, x_{44})^\top

Bold Greek letters for parameters, as in statistics:

Bold Greek letters

LaTeXPreamble: \usepackage{bm}Open in editor
\bm{y} \sim \mathcal{N}(\bm{\mu}, \bm{\Sigma}),
\qquad
\hat{\bm{\beta}} = (\bm{X}^\top \bm{X})^{-1} \bm{X}^\top \bm{y}

\bm and \mathbf side by side:

\bm, \boldsymbol and \mathbf

LaTeXPreamble: \usepackage{bm,amsmath}Open in editor
With \verb|\bm|: $\bm{x}, \bm{\alpha}, \bm{\nabla} f$.
With \verb|\boldsymbol|: $\boldsymbol{x}, \boldsymbol{\alpha}$.
With \verb|\mathbf|: $\mathbf{x}, \mathbf{A}$.

Compatibility

  • From a TeX installation to here: \bm and \boldsymbol work as expected.
  • From here to a TeX installation: documents compile there unchanged. Keep \usepackage{bm}, which a TeX installation needs for \bm.

The full manual is on CTAN: ctan.org/pkg/bm. For other math alphabets, see Math fonts: bold, blackboard, calligraphic.

See also Math basics, Math fonts and physics.

Questions and answers

Should I use \bm or \mathbf for vectors?

Both work here. \bm keeps letters italic and also makes Greek letters bold; \mathbf gives upright letters. Pick one and use it throughout the document.

Every example on this page is typeset by Scissor LaTeX when the site is built. Last updated 2026-11-06.