Marko Petkovšek 1955--2023

During the last months of his life, while still undergoing chemotherapy after a recent severe oncological operation, Marko remained very much engaged in his work. Actually, not only did he collaborate with one of his young students on an article which was later accepted for publication. He co-wrote as well another one on the subject of the representation of prime numbers by quadratic forms with a now deceased surveyor adept at computer experiments. Marko both came up with the formulation and proof of the corresponding hypotheses.