From [this article](http://www.wisdom.weizmann.ac.il/~levina/papers/deconvLevinEtalCVPR09.pdf):

> 
> $\ldots$a maximum-a-postiori "a maximum-a-posteriori
>  $(MAP\_{x,k}^{\,\,\,\,\,1})$ estimation, seeking a pair $(\hat{x}, \hat{k})$ maximizing:
>  $$p(x, k\mid y) \propto p(y\mid x, k)p(x)p(k).$$
> 
> 
> 

What does the symbol '∝' mean in this context?