Mathematical Notation

1.

$\propto$ - proportional to

2.

< or > - less than or greater than

3.

$\ll$ or $\gg$ - much less than or much greater than

4.

$\simeq$ - approximately equal to

5.

$\equiv$ - defined as

6.

$\Delta$x - change in the quantity x

7.

$\Sigma$ - summation sign

8.

|x| - absolute value of x