RS is used in subject-type relative clauses. 

	     +----B----+
	     +-R-+-RS--+
             |   |     |
	The dog who chased me was black

Finite verbs have a B- connector disjoined with their S-
connectors which connects to the main noun of a relative
clause.  This B- is conjoined with a RS-; when the B- is used
to connect back to a noun, an RS connection must be formed as
well. This is supplied by the relative pronoun.

	died arrived: (S- or (RS- & B-));
	who: (R- & (RS+ or C+));

See "R" for a full discussion of relative clauses.

A complicated situation arises when the verb of a subject-type
relative is itself contained in an embedded clause.

             +------B------------+
             +-R-+--C-+-S--+-RS--+
             |   |    |    |     |   
        The dog who John said chased me was black

The "who" makes a C connection to the outer subject of the
relative constituent, just as if it was an object-type
relative.  But in this case, the "B" on the main noun is
connecting to the relative verb as a subject, not an
object. The verb therefore requires a RS connection.
Moreover, the outer verb of the relative constituent, "said",
requires a complement (normally it makes a "TH" or "C"
connection to the subject of a embedded clause: "John SAID HE
was coming"; "*John said"). Thus we give such verbs a "RSe+"
connector, conjoined with their other complement connectors.
(In this situation, the RS link must start a domain; this is
the reason for the "e" subscript.)

Notice that in the above case - unlike other subject-type
relatives - the relative pronoun may be omitted: "The dog
John said chased me was black". This follows naturally from
the current system.

Other "RS" Constructions 
Because the relative pronoun may be omitted here, and because
(either via the relative pronoun or directly) the antecedent
is making a clause connection to the subject of the relative
clause, this situation has a lot in common with object-type
relative clauses; yet the antecedent is the implied subject of
the embedded clause, not the object. In this way, other "B+"
connectors can be used that are normally used in object-type
constructions, for example, those on question-words,
"whatever"-type words, and "transitive" adjectives (the latter
case is a little weird, but we allow it):

	Who do you think hit John
	Whatever you think will work is fine
	?John is easy to think hit Joe