Before revision:  After extending the stabilization procedure of  [ 17 ] to incompressible flow problems, we theoretically prove that, combined with the Raviart-Thomas isogeometric element , we are able to recover the well-posedness of the formulation and, consequently, optimal a priori error estimates.
After revision:  After extending the stabilization procedure of [ 17 ] to incompressible flow problems, we theoretically prove that, combined with the Raviart-Thomas , the N\'ed\'elec, and the Taylor-Hood (in this case, only when the isogeometric map is the identity) isogeometric elements , we are able to recover the well-posedness of the formulation and, consequently, optimal a priori error estimates.