I sometimes see numbers or constants or variables having exponents the operation signs, such as these:
$a^{+},~ a^{-},~ (1/4)^{+},~ k^{\pm},~ 0^{+},~ 0^{-}$
All I know is the zero to the power of plus and minus, which happens for me to know it from learning limits in calculus.
Can someone explain me what do they mean?
Thanks for the answers.
Something superscripted as $+$ or $-$ means the following:
$a^+$ means that we are approaching $a$ from the positive side of $\text{x axis}$ or from the right side.
$a^-$ means that we are approaching it from the $-\text{x axis}$
Thus, $0^-$ means approaching $0$ from left and $0^+$ means approaching it from right side....
This is the same case with all the numbers.