Periodic Schr\"odinger map flow on K\"ahler manifolds

Wei-Yue Ding \cite{Ding 2002} proposeed a proposition about Schr\"odinger map flow in 2002 International Congress of Mathematicians in Beijing, which is called Wei-Yue Ding conjecture by Rodnianski-Rubinstein-Staffilani \cite{Rodnianski 2009}. They proved \cite{Rodnianski 2009} that Schr\"odinger map flow for maps from the real line into K\"ahler manifolds and for maps from the circle into Riemann surfaces is globally well-posed which is the first significant advance in this conjecture by translating the Schr\"odinger map flow into nonlinear Schr\"odinger-type equations or (systems) and partially solved this conjecture. In this article, we will derive a new div-curl type lemma and combined it with energy and ``momentum" balance law to get some space-time estimates. Based on this, we prove the Schr\"odinger map flow for maps from the circle into K\"ahler manifolds is globally regular. So far, the Wei-Yue Ding's conjecture has been completely solved.