On 21 October 2026, the College of Natural Sciences, Can Tho University, was honoured to welcome Professor Michel Théra, Emeritus Professor at Université de Limoges, France, and Professor Alexander Kruger, Emeritus Professor at Federation University Australia, currently affiliated with Ton Duc Thang University, for a visit and research talks in Variational Analysis and Optimisation Theory.
Welcoming the two professors were Assoc. Prof. Dr. Tran Thanh Men - Vice Rector of the College of Natural Sciences, Prof. Dr. Lam Quoc Anh - Vice Rector of the School of Education; and lecturers, postgraduate students, and undergraduate students from the Department of Mathematics.
During the meeting, Professor Michel Théra delivered a talk entitled “The Steiner Selection: Geometry, Stability, and Sensitivity”. The talk explored the Steiner point of a convex body, a construction that plays an important role in convex geometry and set-valued analysis. Professor Théra presented results showing how regularity properties of convex-valued mappings transfer to their Steiner selections, establishing Lipschitz continuity under Hausdorff perturbations. He also discussed differentiability and formulas describing first and second order variations of the Steiner selection, highlighting geometric features arising in polyhedral cases and under smooth deformations.
Professor Alexander Kruger presented “Decoupling Approach to Optimality Conditions and Calculus Rules”. This approach examines the components of a sum of functions at distinct points that approach one another, providing a framework for studying optimality conditions and subdifferential calculus in nonsmooth analysis. The talk focused on the concepts of uniform infimum and uniform lower semicontinuity, their recent extensions implications for sum and intersection rules in non-Lipschitzian settings.
Dr Nguyen Duy Cuong delivered a talk entitled “Optimality Conditions and Solution Set Characterisations of Convex Minimal Time Optimisation Problems”. The talk established dual optimality conditions and characterised entire solution sets using multipliers and subgradients associated with a given solution. These results were applied to optimisation problems involving minimal time functions with different convex dynamics and target sets, including minimal time versions of the Fermat–Torricelli, Chebyshev centre, and p-Fermat–Torricelli problems.
The meeting offered lecturers and students an opportunity to explore advanced research directions in Variational Analysis and Optimization Theory, exchange academic ideas, and strengthen connections with international researchers.
