The two-day workshop, divided into two main thematic blocks – Optimization in Machine Learning and Optimization with Fractional Calculus Methods – is primarily designed for PhD students and other interested participants. The sessions will be conducted by invited lecturers, who are recognized experts in these fields. The proceedings of GPCO 2026 will be published in one of the following forms: • a monograph • a special issue of Optimization: A Journal of Mathematical Programming and Operations Research • a special issue of the International Journal of Applied Mathematics and Computer Science (AMCS)