The intertwining lifting theorem for ordered groups. (Q1874698)

Sz.-Nagy's dilation theorem for a Hilbert space contraction was extended by Mlak to the case of a contraction semigroup whose indices are the positive elements of a totally ordered discrete group. The authors generalize to this case the intertwining lifting theorem of Sz.-Nagy and Foias. Most of the classical interpolation results can thereby be recaptured.