# 数学符号表

## 数学符号表

=

<

>

${\displaystyle x>y}$表示x大于y
${\displaystyle 3<4}$
${\displaystyle 5>4}$

${\displaystyle x\geq y}$表示x大于或等于y
${\displaystyle 3\leq 4}$${\displaystyle 5\leq 5}$
${\displaystyle 5\geq 4}$${\displaystyle 5\geq 5}$

+

×
*

…和…的直积

${\displaystyle \cdot }$

÷

/

${\displaystyle 12/4=3}$

${\displaystyle {\sqrt {}}}$

${\displaystyle {\sqrt {\ }}}$

…的平方根

…的平方根

|　|

…的绝对值
!

…的阶乘

~

${\displaystyle \rightarrow }$可能和${\displaystyle \Rightarrow }$一样，或者有下面将提到的函数的意思

${\displaystyle \supset }$可能和${\displaystyle \Rightarrow }$一样，或者有下面将提到的交集的意思
${\displaystyle x=2\Rightarrow x^{2}=4}$为真，但${\displaystyle x^{2}=4\Rightarrow x=2}$一般情况下为假（x可以是${\displaystyle -2}$

¬

˜

${\displaystyle \neg (\neg A)\Leftrightarrow A}$

${\displaystyle x\neq y\Leftrightarrow \neg (x=y)}$

${\displaystyle A\veebar B}$的意义相同
${\displaystyle (\neg A)\oplus A}$恒为真，${\displaystyle A\oplus A}$恒为假

!

:=

:

${\displaystyle P:\Leftrightarrow Q}$表示${\displaystyle P}$定义为${\displaystyle Q}$的逻辑等价
${\displaystyle \cosh x:={\frac {1}{2}}\left(\exp x+\exp(-x)\right)}$

${\displaystyle A\;{\text{XOR}}\;B:\Leftrightarrow (A\lor B)\land \neg (A\land B)}$

{　,　}

…的集合

{　:　}

{　|　}

${\displaystyle \left\{x|P(x)\right\}}$${\displaystyle \left\{x:P(x)\right\}}$的意义相同
${\displaystyle \left\{n\in \mathbb {N} :n^{2}<20\right\}=\left\{0,1,2,3,4\right\}}$

{}

${\displaystyle \left\{\right\}}$的意义相同
${\displaystyle \left\{n\in \mathbb {N} :1

${\displaystyle a\not \in S}$表示${\displaystyle a}$不属于${\displaystyle S}$

${\displaystyle \left({\frac {1}{2}}\right)^{-1}\in \mathbb {N} }$

${\displaystyle 2^{-1}\not \in \mathbb {N} }$

${\displaystyle A\subset B}$表示${\displaystyle A\subseteq B}$${\displaystyle A\neq B}$

（有的地方记作${\displaystyle A\subsetneqq B}$

${\displaystyle A\cap B\subseteq A}$

${\displaystyle \mathbb {Q} \subset \mathbb {R} }$

${\displaystyle \mathbb {Q} \subsetneqq \mathbb {R} }$

…的子集

${\displaystyle A\supset B}$表示${\displaystyle A\supseteq B}$${\displaystyle A\neq B}$

（有的地方记作${\displaystyle A\supsetneqq B}$

${\displaystyle A\cup B\supseteq B}$

${\displaystyle \mathbb {R} \supset \mathbb {Q} }$

${\displaystyle \mathbb {R} \supsetneqq \mathbb {Q} }$

…的父集

…和…的并集

…和…的交集

\

${\displaystyle \complement }$

（有的地方记作${\displaystyle \complement _{A}B}$

${\displaystyle \left\{1,2,3,4\right\}\setminus \left\{3,4,5,6\right\}=\left\{1,2\right\}}$

${\displaystyle \complement _{U}A=\left\{x|x\in U\ {\textrm {and}}\ x\notin A\right\}}$

(　)

${\displaystyle f(x)}$

${\displaystyle 8\div \left({\frac {4}{2}}\right)={\frac {8}{2}}=4}$

ƒ:X
Y

o

N

N
Z

Z
Q

${\displaystyle \pi \not \in \mathbb {Q} }$
Q
R

${\displaystyle {\sqrt {-1}}\not \in \mathbb {R} }$
R
C

C

π

pi

||　||

…的范数；…的长度

…的直积

'

…撇；…的导数

…的不定积分；…的反导数

…的（delnabla梯度

…的偏导数

…的边界

…的次数

/

 ${\displaystyle \left\{0,a,2a,b,b+a,b+2a\right\}/\left\{0,b\right\}}$ ${\displaystyle =\left\{\left\{0,b\right\},\left\{a,b+a\right\},\left\{2a,b+2a\right\}\right\}}$

## 注释

1. ^ 需注意有时候不同的数学符号有相同含义，而有些数学符号在不同的语境中会有不同的含义。

## 参考资料

1. ^ ISO 80000-2:2009. International Organization for Standardization. [2018-06-15]. （原始内容存档于2014-03-26）.
2. ^ Index of Unicode symbols. Unicode. [2018-06-15]. （原始内容存档于2018-06-15）.