# Math Help - Squiggle arrow... what is it?

1. ## Squiggle arrow... what is it?

Hi. I've met a symbol like this: File:U+21DC.gif - Wikipedia, the free encyclopedia in an equation, at the end of it. In that equation, it was downwards. What is it used for? Thanks!

2. What was the equation? It might be a contradiction...
Contradiction - Wikipedia, the free encyclopedia
4. $g(r)=p_k\left [ \frac{nr(1+r)^n}{(1+r)^n-1} -1 \Downarrow \ \right ]$
Where I've put $\Downarrow$, there is that squiggle arrow.