Altmann, RobertCarstensen, C.2018-01-122018-01-1220120036-1429https://depositonce.tu-berlin.de/handle/11303/7327http://dx.doi.org/10.14279/depositonce-6600The P1-nonconforming finite element is introduced for arbitrary triangulations into quadrilaterals and triangles of multiple connected Lipschitz domains. An explicit a priori analysis for the combination of the Park–Sheen and the Crouzeix–Raviart nonconforming finite element methods is given for second-order elliptic PDEs with inhomogeneous Dirichlet boundary conditions.en510 Mathematiknonconforming finite elementselliptic problemsa priori estimatesArticle1095-7170