2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/79518In this paper, we give a universal family of curves of genus 2 whose jacobians have $\sqrt2$ multiplication fixed by the Rosati involution, and several results based on it, including isogenies between jacobians of curves, and jacobians of curves with quaternionic multiplication.Number Theorytext