Abstract：

In this talk, we will discuss linear equivalences between cuspidal divisors on the moduli stack of Drinfeld shtukas. We exhibit explicit linear equivalences with the help of auxiliary moduli spaces of toy shtukas. Then we use compactification to determine the space of principal cuspidal divisors. Unlike the Manin-Drinfeld theorem for modular curves, in our case, principal cuspidal divisors form a nontrivial subspace of zero degree cuspidal divisors.