  We study the convergence behavior of Dual-Primal Isogeometric Tearing and
Interconnecting (IETI-DP) methods for solving large-scale algebraic systems
arising from multi-patch Isogeometric Analysis. We focus on the Poisson problem
on two dimensional computational domains. We provide a convergence analysis
that covers several choices of the primal degrees of freedom: the vertex
values, the edge averages, and the combination of both. We derive condition
number bounds that show the expected behavior in the grid size h and that are
quasi-linear in the spline degree p.
