> **Possible Duplicate:**  
> [Can we categorify the equation (1 - t)(1 + t + t^2 + …) = 1?](http://mathoverflow.net/questions/1465/can-we-categorify-the-equation-1-t1-t-t2-1)  


Can you give a categorification of the geometric series identity:
$$1/(1-x)=1+x+x^2+...$$
Categorifications of partial sum identities 
$$(1-x^{n+1})/(1-x)=1+x+x^2+...+x^n$$
would also be nice.