A note on toric periods in unramified families

Abstract

Let $A$ be the algebra $\mathbb{C}[X_1^{\pm 1},X_2^{\pm 1}]$ and $Q(A)$ its quotient field. In this short article, we exhibit the correct normalization for the toric period on the parabolically induced unramified family over $Q(A)$, so that it behaves optimally under restriction to the parabolically induced unramified family over $A$. This answers a question raised by D. Prasad, and points towards potential generalizations to a broader unramified Gan-Gross-Prasad setting.

Comments welcomed!