  A new global basis of B-splines is defined in the space of generalized
quadratic splines (GQS) generated by Merrien subdivision algorithm. Then,
refinement equations for these B-splines and the associated corner-cutting
algorithm are given. Afterwards, several applications are presented. First a
global construction of monotonic and/or convex generalized splines
interpolating monotonic and/or convex data. Second, convergence of sequences of
control polygons to the graph of a GQS. Finally, a Lagrange interpolant and a
quasi-interpolant which are exact on the space of affine polynomials and whose
infinite norms are uniformly bounded independently of the partition.
