Drinfeld discriminant function and Fourier expansion of harmonic cochains

Mihran Papikian, Fu-Tsun Wei

Let $F_{\infty }={\mathbb{F}}_q((1/T))$ be the completion of ${\mathbb{F}}_q(T)$ at $1/T$. We develop a theory of Fourier expansions for harmonic cochains on the edges of the Bruhat-T…