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7 hamstring stretches recommended by a physical therapist

Popular Science

The best ways to maximize mobility and even prevent back pain. Walk, work and wake better with these hamstring stretches. Breakthroughs, discoveries, and DIY tips sent six days a week. We have some news you're gonna want to sit down for--but you probably shouldn't: Your hamstrings are, in all likelihood, an anatomical disaster for a number of possible reasons, not least of which being excessive time spent seated on them. "The hamstrings are three muscles located on the back of your thigh, and they're responsible for bending your knee and extending your hip," says Marissa Cummo, PT, DPT, assistant director of physical therapy at NYC Health + Hospitals Bellevue .










A Unified Kantorovich Duality for Multimarginal Optimal Transport

Cheryala, Yehya, Alaya, Mokhtar Z., Bouzebda, Salim

arXiv.org Machine Learning

Multimarginal optimal transport (MOT) has gained increasing attention in recent years, notably due to its relevance in machine learning and statistics, where one seeks to jointly compare and align multiple probability distributions. This paper presents a unified and complete Kantorovich duality theory for MOT problem on general Polish product spaces with bounded continuous cost function. For marginal compact spaces, the duality identity is derived through a convex-analytic reformulation, that identifies the dual problem as a Fenchel-Rockafellar conjugate. We obtain dual attainment and show that optimal potentials may always be chosen in the class of $c$-conjugate families, thereby extending classical two-marginal conjugacy principle into a genuinely multimarginal setting. In non-compact setting, where direct compactness arguments are unavailable, we recover duality via a truncation-tightness procedure based on weak compactness of multimarginal transference plans and boundedness of the cost. We prove that the dual value is preserved under restriction to compact subsets and that admissible dual families can be regularized into uniformly bounded $c$-conjugate potentials. The argument relies on a refined use of $c$-splitting sets and their equivalence with multimarginal $c$-cyclical monotonicity. We then obtain dual attainment and exact primal-dual equality for MOT on arbitrary Polish spaces, together with a canonical representation of optimal dual potentials by $c$-conjugacy. These results provide a structural foundation for further developments in probabilistic and statistical analysis of MOT, including stability, differentiability, and asymptotic theory under marginal perturbations.