Gamma in LaTeX (\gamma)

Where it is used

Lowercase Greek gamma, used for the Euler-Mascheroni constant, the Lorentz factor, and discount factors.

\gamma is the Lorentz factor \gamma = 1/\sqrt{1 - v^2/c^2} in special relativity and the Euler-Mascheroni constant \gamma \approx 0.5772 in analysis. Reinforcement learning uses it as the discount factor in \sum_t \gamma^t r_t, and physics uses it for gamma rays and photons. In geometry it often names the third angle of a triangle after \alpha and \beta, and in complex analysis \gamma is a curve or contour. Note the uppercase \Gamma, which is the gamma function, is a separate command; do not write \Gamma for the constant.

Minimal compilable example

Paste this into an empty .tex file and compile it with pdfLaTeX, XeLaTeX or LuaLaTeX.

\documentclass{article}
\begin{document}
Gamma: $\gamma$

\[ G_t = \sum_{k=0}^{\infty} \gamma^{k} r_{t+k+1} \]
\end{document}

Related symbols

• Gamma (Upper)\Gamma
• Beta\beta
• Delta\delta
• Alpha\alpha
• Delta (Upper)\Delta
• Epsilon\epsilon

Frequently asked questions

How do I write Gamma in LaTeX?

Type \gamma in math mode, for example $G_t = \sum_{k=0}^{\infty} \gamma^{k} r_{t+k+1}$. It works in plain LaTeX without loading any package.

Which package do I need for \gamma?

None. \gamma is part of standard LaTeX, so it compiles with nothing in the preamble but the document class.

Can I use \gamma in text mode, or only in math mode?

Only in math mode. Outside $...$ LaTeX stops with "Missing $ inserted", so write $\gamma$ in running text. If you only need the glyph in text, paste the Unicode character γ instead (with XeLaTeX or LuaLaTeX and a font that has it).