Topic consists of that part of the sentence that connects it to the preceding context - its meaning connects to expressions that have already appeared in the text, to facts deducible from them or to facts assumed to be known to the addressee.
We assume that in a tectogrammatical tree, the topic consists of the following nodes:
the effective root of the sentence (the node representing the governing verb) if its tfa value is t
nodes with the value t in the attribute tfa dependent on the effective root of the sentence which are not ancestors of the focus proper (see Section 3.1.1, "Focus proper"), and all their descendant nodes.
nodes with the value c in the attribute tfa dependent on the effective root of the sentence and all their descendant nodes.
In the tectogrammatical trees, the topic is placed on the left.
We consider the contrastive topic to be part of the topic - see Section 5.1.1, "Contrastive topic".
Connecting into the context using contrast is a specific type of contextual boundness. A certain part of a new sentence is put into contrast with some fact known from the preceding context.
We call the contrastive contextually bound part of the topic contrastive topic .
We assume that in a tectogrammatical tree, a contrastive topic consists of the following nodes:
nodes with the value c in the attribute tfa and all their descendant nodes.