【转】latexSymbol

This article will provide a short list of commonly used LaTeX symbols.

Finding Other Symbols

Here are some external resources for finding less commonly used symbols:

Detexify is an app which allows you to draw the symbol you'd like and shows you the $\text{\LaTeX}$ code for it!
MathJax (what allows us to use $\text{\LaTeX}$ on the web, (technically an AJAX library simulating it.)) maintains a list of supported commands.
The Comprehensive LaTeX Symbol List.

Operators

Symbol	Command	Symbol	Command	Symbol	Command
$\pm$	\pm	$\mp$	\mp	$\times$	\times
$\div$	\div	$\cdot$	\cdot	$\ast$	\ast
$\star$	\star	$\dagger$	\dagger	$\ddagger$	\ddagger
$\amalg$	\amalg	$\cap$	\cap	$\cup$	\cup
$\uplus$	\uplus	$\sqcap$	\sqcap	$\sqcup$	\sqcup
$\vee$	\vee	$\wedge$	\wedge	$\oplus$	\oplus
$\ominus$	\ominus	$\otimes$	\otimes	$\circ$	\circ
$\bullet$	\bullet	$\diamond$	\diamond	$\lhd$	\lhd
$\rhd$	\rhd	$\unlhd$	\unlhd		\unrhd
$\oslash$	\oslash	$\odot$	\odot	$\bigcirc$	\bigcirc
$\triangleleft$	\triangleleft	$\Diamond$	\Diamond	$\bigtriangleup$	\bigtriangleup
$\bigtriangledown$	\bigtriangledown	$\Box$	\Box	$\triangleright$	\triangleright
$\setminus$	\setminus	$\wr$	\wr	$\sqrt{x}$	\sqrt
$x^{\circ}$	x^	$\triangledown$	\triangledown	$\sqrt[n]{x}$	\sqrt[n]
	a^x	$a^{xyz}$	a^		a_x

Relations

Symbol	Command	Symbol	Command	Symbol	Command
$\le$	\le	$\ge$	\ge	$\neq$	\neq
$\sim$	\sim	$\ll$	\ll	$\gg$	\gg
$\doteq$	\doteq	$\simeq$	\simeq	$\subset$	\subset
$\supset$	\supset	$\approx$	\approx	$\asymp$	\asymp
$\subseteq$	\subseteq	$\supseteq$	\supseteq	$\cong$	\cong
$\smile$	\smile	$\sqsubset$	\sqsubset	$\sqsupset$	\sqsupset
$\equiv$	\equiv	$\frown$	\frown	$\sqsubseteq$	\sqsubseteq
$\sqsupseteq$	\sqsupseteq	$\propto$	\propto	$\bowtie$	\bowtie
$\in$	\in	$\ni$	\ni	$\prec$	\prec
$\succ$	\succ	$\vdash$	\vdash	$\dashv$	\dashv
$\preceq$	\preceq	$\succeq$	\succeq	$\models$	\models
$\perp$	\perp	$\parallel$	\parallel
$\mid$	\mid	$\bumpeq$	\bumpeq

Negations of many of these relations can be formed by just putting \not before the symbol, or by slipping an n between the \ and the word. Here are a couple examples, plus many other negations; it works for many of the many others as well.

Symbol	Command	Symbol	Command	Symbol	Command
$\nmid$	\nmid	$\nleq$	\nleq	$\ngeq$	\ngeq
$\nsim$	\nsim	$\ncong$	\ncong	$\nparallel$	\nparallel
$\not<$	\not<	$\not>$	\not>	$\not=$	\not= or \neq
$\not\le$	\not\le	$\not\ge$	\not\ge	$\not\sim$	\not\sim
$\not \approx$	\not\approx	$\not\cong$	\not\cong	$\not\equiv$	\not\equiv
$\not\parallel$	\not\parallel	$\nless$	\nless	$\ngtr$	\ngtr
$\lneq$	\lneq	$\gneq$	\gneq	$\lnsim$	\lnsim
$\lneqq$	\lneqq	$\gneqq$	\gneqq

To use other relations not listed here, such as =, >, and <, in LaTeX, you must use the symbols on your keyboard, they are not available in $\LaTeX$ .

Greek Letters

Symbol	Command	Symbol	Command	Symbol	Command	Symbol	Command
$\alpha$	\alpha	$\beta$	\beta	$\gamma$	\gamma	$\delta$	\delta
$\epsilon$	\epsilon	$\varepsilon$	\varepsilon	$\zeta$	\zeta	$\eta$	\eta
$\theta$	\theta	$\vartheta$	\vartheta	$\iota$	\iota	$\kappa$	\kappa
$\lambda$	\lambda	$\mu$	\mu	$\nu$	\nu	$\xi$	\xi
$\pi$	\pi	$\varpi$	\varpi	$\rho$	\rho	$\varrho$	\varrho
$\sigma$	\sigma	$\varsigma$	\varsigma	$\tau$	\tau	$\upsilon$	\upsilon
$\phi$	\phi	$\varphi$	\varphi	$\chi$	\chi	$\psi$	\psi
$\omega$	\omega

Symbol	Command	Symbol	Command	Symbol	Command	Symbol	Command
$\Gamma$	\Gamma	$\Delta$	\Delta	$\Theta$	\Theta	$\Lambda$	\Lambda
$\Xi$	\Xi	$\Pi$	\Pi	$\Sigma$	\Sigma	$\Upsilon$	\Upsilon
$\Phi$	\Phi	$\Psi$	\Psi	$\Omega$	\Omega

Arrows

Symbol	Command	Symbol	Command
$\gets$	\gets	$\to$	\to
$\leftarrow$	\leftarrow	$\Leftarrow$	\Leftarrow
$\rightarrow$	\rightarrow	$\Rightarrow$	\Rightarrow
$\leftrightarrow$	\leftrightarrow	$\Leftrightarrow$	\Leftrightarrow
$\mapsto$	\mapsto	$\hookleftarrow$	\hookleftarrow
$\leftharpoonup$	\leftharpoonup	$\leftharpoondown$	\leftharpoondown
$\rightleftharpoons$	\rightleftharpoons	$\longleftarrow$	\longleftarrow
$\Longleftarrow$	\Longleftarrow	$\longrightarrow$	\longrightarrow
$\Longrightarrow$	\Longrightarrow	$\longleftrightarrow$	\longleftrightarrow
$\Longleftrightarrow$	\Longleftrightarrow	$\longmapsto$	\longmapsto
$\hookrightarrow$	\hookrightarrow	$\rightharpoonup$	\rightharpoonup
$\rightharpoondown$	\rightharpoondown	$\leadsto$	\leadsto
$\uparrow$	\uparrow	$\Uparrow$	\Uparrow
$\downarrow$	\downarrow	$\Downarrow$	\Downarrow
$\updownarrow$	\updownarrow	$\Updownarrow$	\Updownarrow
$\nearrow$	\nearrow	$\searrow$	\searrow
$\swarrow$	\swarrow	$\nwarrow$	\nwarrow

(For those of you who hate typing long strings of letters, \iff and \implies can be used in place of \Longleftrightarrow and \Longrightarrow respectively.)

Dots

Symbol	Command	Symbol	Command
$\cdot$	\cdot	$\vdots$	\vdots
$\dots$	\dots	$\ddots$	\ddots
$\cdots$	\cdots	$\iddots$	\iddots

Accents

Symbol	Command	Symbol	Command	Symbol	Command
$\hat{x}$	\hat	$\check{x}$	\check	$\dot{x}$	\dot
$\breve{x}$	\breve	$\acute{x}$	\acute	$\ddot{x}$	\ddot
$\grave{x}$	\grave	$\tilde{x}$	\tilde	$\mathring{x}$	\mathring
$\bar{x}$	\bar	$\vec{x}$	\vec

When applying accents to i and j, you can use \imath and \jmath to keep the dots from interfering with the accents:

Symbol	Command	Symbol	Command
$\vec{\jmath}$	\vec	$\tilde{\imath}$	\tilde

\tilde and \hat have wide versions that allow you to accent an expression:

Symbol	Command	Symbol	Command
$\widehat{7+x}$	\widehat	$\widetilde{abc}$	\widetilde

Others

Symbol	Command	Symbol	Command	Symbol	Command
$\infty$	\infty	$\triangle$	\triangle	$\angle$	\angle
$\aleph$	\aleph	$\hbar$	\hbar	$\imath$	\imath
$\jmath$	\jmath	$\ell$	\ell	$\wp$	\wp
$\Re$	\Re	$\Im$	\Im	$\mho$	\mho
$\prime$	\prime	$\emptyset$	\emptyset	$\nabla$	\nabla
$\surd$	\surd	$\partial$	\partial	$\top$	\top
$\bot$	\bot	$\vdash$	\vdash	$\dashv$	\dashv
$\forall$	\forall	$\exists$	\exists	$\neg$	\neg
$\flat$	\flat	$\natural$	\natural	$\sharp$	\sharp
$\backslash$	\backslash	$\Box$	\Box	$\Diamond$	\Diamond
$\clubsuit$	\clubsuit	$\diamondsuit$	\diamondsuit	$\heartsuit$	\heartsuit
	\spadesuit	$\Join$	\Join	$\blacksquare$	\blacksquare
$\S$	\S	$\P$	\P	$\copyright$	\copyright
$\pounds$	\pounds	$\overarc{ABC}$	\overarc	$\underarc{XYZ}$	\underarc
$\bigstar$	\bigstar	$\in$	\in	$\cup$	\cup
$\square$	\square
$\smiley$	\smiley
$\mathbb{R}$	\mathbb{R} (represents all real numbers)
$\checkmark$	\checkmark
$\cancer$	\cancer

Command Symbols

Some symbols are used in commands so they need to be treated in a special way.

Symbol	Command	Symbol	Command	Symbol	Command	Symbol	Command
$\textdollar$	\textdollar or $		&		%		#
	_		{		}	$\backslash$	\backslash

(Warning: Using $ for $\textdollar$ will result in $$$$ . This is a bug as far as we know. Depending on the version of $\LaTeX$ this is not always a problem.)

European Language Symbols

Symbol	Symbol	Symbol	Command	Symbol
${\oe}$	${\ae}$	${\o}$
${\OE}$	${\AE}$	${\AA}$		${\O}$
${\l}$	${\ss}$	$\text{!`}$	!`
${\L}$	${\SS}$

Bracketing Symbols

In mathematics, sometimes we need to enclose expressions in brackets or braces or parentheses. Some of these work just as you'd imagine in LaTeX; type ( and ) for parentheses, [ and ] for brackets, and | and | for absolute value. However, other symbols have special commands:

Symbol	Command	Symbol	Command	Symbol	Command
${$	{	$}$	}		\|
$\backslash$	\backslash	$\lfloor$	\lfloor	$\rfloor$	\rfloor
$\lceil$	\lceil	$\rceil$	\rceil	$\langle$	\langle
$\rangle$	\rangle

You might notice that if you use any of these to typeset an expression that is vertically large, like

the parentheses don't come out the right size:

If we put \left and \right before the relevant parentheses, we get a prettier expression:

gives

And with system of equations:

\left\{\begin{array}{l}x+y=3\\2x+y=5\end{array}\right.

Gives

$\left{\begin{array}{l}x+y=3\2x+y=5\end{array}\right.$

See that there's a dot after \right. You must put that dot or the code won't work.

In addition to the \left and \right commands, when doing floor or ceiling functions with fractions, using

\left\lceil\frac{x}{y}\right\rceil

and \left\lfloor\frac{x}{y}\right\rfloor

give both $\left\lceil\frac{x}{y}\right\rceil\text{ and }\left\lfloor\frac{x}{y}\right\rfloor\text{, respectively.}$

And, if you type this

\underbrace{a_0+a_1+a_2+\cdots+a_n}_{x}

Gives

$\underbrace{a_0+a_1+a_2+\cdots+a_n}_{x}$

\overbrace{a_0+a_1+a_2+\cdots+a_n}^{x}

Gives

$\overbrace{a_0+a_1+a_2+\cdots+a_n}^{x}$

\left and \right can also be used to resize the following symbols:

Symbol	Command	Symbol	Command	Symbol	Command
$\uparrow$	\uparrow	$\downarrow$	\downarrow	$\updownarrow$	\updownarrow
$\Uparrow$	\Uparrow	$\Downarrow$	\Downarrow	$\Updownarrow$	\Updownarrow

Multi-Size Symbols

Some symbols render differently in inline math mode and in display mode. Display mode occurs when you use [...] or $$...$$, or environments like \begin{equation}...\end{equation}, \begin{align}...\end{align}. Read more in the commands section of the guide about how symbols which take arguments above and below the symbols, such as a summation symbol, behave in the two modes.

In each of the following, the two images show the symbol in display mode, then in inline mode.

Symbol	Command	Symbol	Command	Symbol	Command
$\sum \textstyle\sum$	\sum	$\int \textstyle\int$	\int	$\oint \textstyle\oint$	\oint
$\prod \textstyle\prod$	\prod	$\coprod \textstyle\coprod$	\coprod	$\bigcap \textstyle\bigcap$	\bigcap
$\bigcup \textstyle\bigcup$	\bigcup	$\bigsqcup \textstyle\bigsqcup$	\bigsqcup	$\bigvee \textstyle\bigvee$	\bigvee
$\bigwedge \textstyle\bigwedge$	\bigwedge	$\bigodot \textstyle\bigodot$	\bigodot	$\bigotimes \textstyle\bigotimes$	\bigotimes
$\bigoplus \textstyle\bigoplus$	\bigoplus	$\biguplus \textstyle\biguplus$	\biguplus