Abstract

Taking into account that no subordering of a scattered partial ordering is dense, we are going to define one idea of rank of a partial ordering which will make possible an equivalent but more operative definition of a scattered partial ordering. Using this notion of rank and the Scott’s sentence associated with the ordering, we are going to characterise in the infinitary language Lw1.w each element of a subclass of the partial orderings, this of the strongly scattered countable partial orderings.