During my visits to several schools in villages and nearby semi-urban areas, I encountered a troubling contradiction at the ...

The world today is marked by paradox. Never before has humanity possessed such extraordinary scientific knowledge, ...

程伟、魏文学Hamilton动力系统中的Mather商集问题可以从拓扑和变分两个观点来进行研究。本文从微分几何的角度，利用Ricci曲率以及一阶上同调来估计弱KAM解的二阶导数性质，从而得到有关Mather商集问题的一些几何结论。Aubry-Math ...