How do you write lambda(λ,Λ) symbol in LaTeX?

The Greek alphabet lambda is often used in mathematics and physics.

So, both uppercase and lowercase of the lambda symbol can be used in different ways in creating scientific documents in LaTeX.

In this tutorial, we will discuss all methods of using lambda symbols in LaTeX.

Small lambda(λ) in LaTeX

LaTeX provides a default command to print the small lambda symbol in a LaTeX document, which is \lambda .

And if you want to use superscript and subscript with this symbol then you can use like this:

\lambda^{superscript}_{subscript}

\documentclass{article}
\usepackage{amsmath} % for \longrightarrow and bmatrix
\begin{document}
  \[ \verb|\lambda|\longrightarrow\lambda \]
  \[\begin{bmatrix}
     \lambda_1 &  &  & \\
     & \lambda_2 &  & \\
     &  & \ddots &  \\
     &  &  & \lambda_n 
    \end{bmatrix} \]
  \[ \sum^n_{i=k} \mu_A\left(\frac{1}{\lambda_i}\right) \] 
  \[ \mathrm{det}(A)=\prod^{N_\lambda}_{i=1} \lambda^{n_i}_{i} \]
  \[ (A-\lambda_1)^{\mu(\lambda_1)}(A-\lambda_2)^{\mu(\lambda_2)}\cdots(A-\lambda_n)^{\mu(\lambda_n)} \]
  \[ \frac{d}{dx}\mathrm{e}^{\lambda x}=\lambda \mathrm{e}^{\lambda x} \]
\end{document}

Output :

1. Italic Small lambda symbol

You can also print the small lambda symbol in italic font. As you can see in the example above, the default \lambda command output does not look like this 𝜆.

So for this you need to use a package called txfonts. And now if you use the \lambda command, the italic small lambda symbol will be printed in the LaTeX document.

\documentclass{article}
\usepackage{amsmath} % for \longrightarrow and bmatrix
\usepackage{txfonts} % for italic small lambda
\begin{document}
  \[ \verb|\usepackage{txfonts}| \]
  \[ \verb|\lambda|\longrightarrow\lambda \]
  \[\begin{bmatrix}
     \lambda_1 &  &  & \\
     & \lambda_2 &  & \\
     &  & \ddots &  \\
     &  &  & \lambda_n 
    \end{bmatrix} \]
  \[ \mathrm{diag}(\lambda_1,\lambda_2,\dots,\lambda_{n-1},\lambda_n) \]
  \[ \sum_{n\leq\lambda}\left(1-\frac{n}{\lambda}\right)^\delta \] 
  \[ \mathrm{det}(A)=\prod^{N_\lambda}_{i=1} \lambda^{n_i}_{i} \]
  \[ \frac{d}{dx}\mathrm{e}^{\lambda x}=\lambda \mathrm{e}^{\lambda x} \]
\end{document}

Output :

2. lambdabar(ƛ) symbol

You need the revsymb package to print the lambdabar symbol to a latex document.

This package provides a command which is \lambdabar, by this command, you can print this lambdabar symbol.

Also if you want to print italic lambdabar symbol then you need to use txfonts package and use the same command \lambdabar.

Package	command and output
revsymb	\lambdabar →
txfonts	\lambdabar →
None	\overline{\lambda} →
None	\bar{\lambda} →

Capital Lambda(Λ) in LaTeX

LaTeX provides a default command called \Lambda to print the big lambda or capital lambda symbol in a LaTeX document.

And if you want to use superscript and subscript with it then you can use like this.

\Lambda^{superscript}_{subscript}

\documentclass{article}
\usepackage{amsmath} % for \longrightarrow
\begin{document}
  \[ \verb|\Lambda|\longrightarrow\lambda \]
  \[ \Lambda^0 \quad \Lambda^+_c \quad \Lambda^0_b \quad \Lambda^+_t \]
  \[ \log (n)=\sum_{d|n}\Lambda(d) \]
  \[ \Lambda_k(n)=\sum_{d|n}\mu(d)\log^k(n/d) \]
  \[ \sum_{i\geq x}\frac{\Lambda(i)}{i} \]
\end{document}

Output :

1. Capital Lambda using upgreek package

You can use the upgreek package to get a slightly different output of the capital lambda symbol.

This package provides a command called \Uplambda, which gives you a slightly different output of capital lambda symbols.

\documentclass{article}
\usepackage{amsmath} % for \longrightarrow
\usepackage{upgreek} % for slightly different big Lambda output 
\begin{document}
  \[ \verb|\Lambda|\longrightarrow\Lambda \]
  \[ \verb|\Uplambda|\longrightarrow\Uplambda \]
\end{document}

Output :

Bold lambda symbol in LaTeX

LaTeX provides a default command which is \mathbf{}, by this command, you can print capital lambda symbols in bold font but small lambda symbols cannot be printed in bold by this command.

So, if you want to print a symbol in bold then the best package for that is bm.

This package provides a command called \bm{} that allows you to print any symbol in a document in bold font.

\documentclass{article}
\usepackage{amsmath} % for \longrightarrow
\usepackage{txfonts} % for italic lambda and lambdabar 
\usepackage{bm} % for bold symbols 
\begin{document}
  \verb|\Lambda|$\longrightarrow\Lambda $\\[4pt]
  \verb|\mathbf{\Lambda}|$\longrightarrow\mathbf{\Lambda} $\\[4pt]
  \verb|\bm{\Lambda}|$\longrightarrow\bm{\Lambda} $\\[4pt]
  \verb|\Lambda|$\longrightarrow\Lambda $\\[4pt]
  \verb|\bm{\lambda}|$\longrightarrow\bm{\lambda} $\\[4pt]
  \verb|\bm{\lambdabar}|$\longrightarrow\bm{\lambdabar} $
\end{document}

Output :