对椭圆边值问题,利用离散最小二乘恢复技巧和局部对称技巧,对导数进行后处理,证明了二次三角形元在局部对称点上导数存在O(h^4)的强超收敛性.
For elliptic boundary value problem, a post-process method is proposed by using discrete least-square patch recovery technique and locally symmetric technique, We obtained O(h^4) ultraconvergence for quadraic triangular finite element at locally symmetric points.