Non-commutative Iwasawa theory of abelian varieties over global function fields

Abstract: Let $A$ be an abelian variety defined over a global function field $F$. We investigate the structure of the $p$-primary Selmer group $\mathrm{Sel}(A/F_\infty)$ for any prime number $p$ distinct from the characteristic of $F$, over $p$-adic Lie extensions $F_\infty$ of $F$ which contain the cyclotomic $\mathbb{Z}p$-extension $F^{\mathrm{cyc}}$. In particular, we prove that the Pontryagin dual of the Selmer group $\mathrm{Sel}(A/F^\mathrm{cyc})$ is a torsion $\mathbb{Z}_p[[\mathrm{Gal}(F^\mathrm{cyc}/F)]]$-module with trivial $\mu$-invariant, and we establish the $\mathfrak{M}_H(G)$-conjecture of Coates-Fukaya-Kato-Sujatha-Venjakob for $A/F\infty$. In view of the validity of the $\mathfrak{M}H(G)$-conjecture, it therefore makes sense to speak of the characteristic element (in the sense of Coates et al.) attached to the Pontryagin dual of $\mathrm{Sel}(A/F\infty)$. We relate the order of vanishing of the characteristic elements, evaluated at Artin representations, to the corank of the Selmer group of the corresponding twist of $A$ over the base field $F$. Combining this with the deep results of Tate, Milne and Kato-Trihan, we show that the order of vanishing of the characteristic elements is equal to the order of vanishing of the $L$-function of $A/F$ at $s=1$ under appropriate assumptions. Finally, we relate the generalised Euler characteristic of $\mathrm{Sel}(A/F_\infty)$ to the Euler characteristic of $\mathrm{Sel}(A/F^{\mathrm{cyc}})$. This is a natural analogue of Zerbes' result in the number field context and generalises previous results of Sechi and Valentino in the function field context.