I propose the following focus mappings for Russian; these mappings
warrant further investigation, but they provide a starting point for
future research into the interaction of c-structure and i-structure.
With contrastive focus the relevant node is annotated with ( 
PRED
FN) 
( 
FOC).
This will place the relevant core PRED in the FOC of the
i-structure. Additional annotations can be used to indicate subtypes
of discourse functions, e.g., prominence for contrastive focus. In
addition, a mapping must be made to the prosodic structure to assign
appropriate intonation; this is not formalised here. New information
focus involves annotating clause-final leaf nodes from right to left
with ( PRED FN) ( FOC) and assigning
default falling intonation to the clause.
Other discourse function mappings in Russian include the c-structure
rule annotations on SpecIP for topics. Topic will also be assigned to
all pro-dropped elements since in Russian topichood is a necessary,
but not sufficient, requirement for pro-drop. The default
assignment of items is to neutral or background information (see Butt and
King 1996 on further differentiating types of background
information).
Consider the sentence, repeated in (20), which contains a contrastively focused verb.
(20)
The c-structure rules result in the i-structure annotations
in (21) (annotations giving grammatical function information are
not shown) whereby the subject's PRED FN is the value of
TOP.
(21)
The focus rules then assign the verb's PRED FN to be an element of FOC. The fact that it is a contrastive focus can be captured by further annotations.
(22)
Finally, all PREDs which are not assigned a discourse function are designated as background information. Here this is shown by further annotations on the c-structure tree. However, it may be that this assignment is the result of constraints and mapping between i-structure and s-structure. That is, there independently must be a mapping between s-structure and i-structure which ensures that all items with PREDs receive a discourse function. This may also allow free assignment of PREDs to the BCK role. Items which already have a role will not be assigned another due to the i-structure equivalent of coherence.
(23)
These annotations in addition to the assignment of f-structure grammatical relations result in the f- and i-structures shown in (24). Note that while the verb's f-structure PRED still has its argument structure, the i-structure's does not.
(24) F-structure
I-structure
Sub-constituent focus works similarly, as seen below. The subject is
assigned to TOP due to its c-structure position in SpecIP, while the verb
and its objects are assigned to FOC.\
(25)
(26)
The resulting f-structure is identical to that of the corresponding sentence with contrastive focus on the verb. This is the desired result since the basic grammatical functions of the two sentences are identical; they differ only in their i-structure content. The i-structure of (25) is shown in (27).
(27) F-structure = (24)
I-structure
