Complex predicates have been discussed for decades. A favorite topic has been their passives, so-called long passives (e.g. Norwegian Dette unngås å gjøres 'this avoid.PASS to do.PASS'). The realization of the long passive shows interesting variation in Norwegian. Not only is the first verb passive, the second verb also often is. Norwegian has an inflectional and a periphrastic passive, and both can be used. However, the inflectional passive is preferred with both verbs, even if it is in general the "marked" passive realization. I will discuss this variation and its grammatical treatment, and compare Norwegian to Swedish and French.
Helge Lødrup (Thu,) studied this question.