Anisotropic NURBS approximation in isogeometric analysis

We investigate the approximation error of mapped NURBS spaces, such as those used in isogeometric analysis in accordance to the isoparametric paradigm. We extend the results of [6] to the case of anisotropic meshes, such as those needed in the presence of boundary layers. The theoretical results cover anisotropic h-refinement and are supported by numerical tests involving different geometries.