Approximation Schemes for k-Subset Sum Ratio and Multiway Number Partitioning Ratio. - Sotiris Kanellopoulos; Giorgos Mitropoulos; Antonis Antonopoulos; Nikos Leonardos; Aris Pagourtzis; Christos Pergaminelis; Stavros Petsalakis; Kanellos Tsitouras (CoRR, 2025)