Sigma summation notation with negative index

Question

I came across this notation reading in an economics publication. $q = 1 \vee q = 0$. I'm unfamiliar with negative indices in this context and wonder whether the authors are including $j=0$.

References:

Meghir, & Pistaferri (2004). Income variance dynamics and heterogeneity. Econometrica

Answer 1

It looks to me that the summation notation means the sum for index $j$ (should be an integer) from $-(1+q)$ to $(1+q)$, and so $j=0$ should be included.