Explicit valuation of elliptic nets for elliptic curves with complex multiplication

Division polynomials associated to an elliptic curve $E/K$ are polynomials $ϕ_n, ψ_n^2$ that arise from the sequence of points ${nP}{n \in \mathbb{N}}$ on this curve. If one wishes to study $\mathbb{Z}$–linear combination of points on $E(K)$, we can use net polynomials $Φ{v}, Ψ_{v}^2$ which are higher–dimensional analogue of division polynomials. It turns out they are also elliptic nets, an $n$–dimensional array with values in $K$ satisfying the same nonlinear recurrence relation that division polynomials do as well. Now further assume the elliptic curve $E/K$ has complex multiplication by an order of a quadratic imaginary field $F \subseteq K$, we will prove a formula for the common valuation of $Φ_{v}$ and $Ψ_{v}^2$ associated to multiples of points by elements of an order in $F$. As an application, we will use the formula to show that elliptic divisibility sequences associated to multiples of points indexed by elements of an order also satisfy a recurrence relation when indexed by elements of an order, subject to certain conditions on the indices. Additionally, we also expect that the formula may also be used in computing $\mathcal{O}_K$–integral points of an elliptic curve of rank $2$ with complex multiplication (this is future work).

💡 Research Summary

The paper studies elliptic nets—multivariate generalizations of the classical division polynomials—on elliptic curves that admit complex multiplication (CM). For a curve (E/K) with (\operatorname{End}(E)=\mathbb Z