Jens Brandt focused on enhancing the correctness of number field computations in the Hecke.jl repository, specifically addressing a critical bug in NumberField.jl related to surjectivity checks for number field homomorphisms. By carefully correcting a misplaced bracket in the is_surjective function and refining the comparison of absolute degrees between domain and codomain, Jens ensured that surjectivity is now determined accurately, preventing downstream computational errors. This work, implemented in Julia and leveraging expertise in mathematical software and bug fixing, improved the reliability and maintainability of algebraic analyses in Hecke.jl, demonstrating a precise and thoughtful approach to mathematical software engineering.