Explicit Coleman integration over finite extensions of $\mathbb{Q}_p$

Source abstract

Coleman integration is an important computational ingredient of the Chabauty--Coleman method and its extensions. We extend the Balakrishnan--Tuitman algorithm to general smooth projective curves with good reduction over arbitrary finite extensions of $\mathbb{Q}_p$, allowing both ramification and nontrivial residue degree. Given a suitable plane model and integral bases, we provide explicit precision bounds and an accompanying Magma implementation. As an application, a single-prime computation at $p=19$ over the unramified quadratic extension $\mathbb{Q}_{19^2}/\mathbb{Q}_{19}$ recovers all $35$ affine sporadic quadratic divisors on $X(s3,ns5)$ over $\mathbb{Q}(\sqrt5)$. Completeness is proved in an appendix using symmetric Chabauty and a Mordell--Weil sieve.