On a Conjecture about an analogue of Tokuyama's theorem for G₂

We prove the conjecture of Friedlander et al. about sums over Littelmann patterns for the the root system of type $G_2$, which is an analogue of Tokuyama's theorem for root systems of type $A_r$. We use elementary means to show that the conjecture is implied by a finite set of polynomial identities.