A "typed" assertion is an assertion that specifies its assertion type (i.e., that has an AT arc and t-node). The semantics of a typed assertion are determined by the subject of its t-node, which is the assertion type of which the typed assertion is an instance. The subject of the t-node incorporates the semantics of all of the role types that can have role players in instances of the assertion type, all of which must be specified in the definition of the subject of the assertion type, either by reference or inclusion.

The first sentence is redundant with the glossary. The third
sentence appears to say that the subject of a t-node incorporates "all
the role types that can have role players in instances of the assertion
type," but there is only one assertion type (the t-node) so it is not
clear what is being gathered up as "all of the role types...?"