S connects subject-nouns to finite verbs:

             +-S---+
	     |     |
	The dog chased the cat

All nouns carry an S+ connector. Many other words that can act
as noun-phrases (or heads of noun-phrases) carry S+ as
well. These include nominative pronouns ("she", but not
"her"); determiners like "many", "all", and "this";
miscellaneous words like "someone", "everything", "what", and
"whatever"; numbers; possessives like "hers" and "mine";
gerunds; and adjectives (here a definite determiner is
required; see "DD").

     Contents
     1. Ss and Sp: Noun-verb agreement
     1. Special S links
     2. Ss#g: Gerunds
     3. Gerunds: The complement / no determiner case
     4. Gerunds: The no complement / determiner case
     5. Gerunds with neither determiner nor complement
     6. Noun-modifiers on gerunds
     7. The use of gerunds
     8. "Urfl-only" domains

Ss and Sp: noun-verb agreement 
Ss connects singular nouns words to singular verb forms ("The
dog chases the cat"); Sp connects plural nouns to plural verb
forms ("The dogs chase the cat"). Other noun-phrase words take
Ss+ or Sp+, as appropriate; with noun-phrase determiners, for
example, some take Ss+ ("this"), some take Sp+ ("many"), and
some take S+ ("all"), allowing connections with either
singular or plural verbs. Proper nouns carry Ss+, and thus are
assumed to be singular, as they generally are. Simple-past
verb forms do not distinguish between singular and plural
("The dog chased the cat", "The dogs chased the cat"); thus an
unsubscripted S- is used.

A few seemingly singular nouns can sometimes take plural verb
forms: "A majority are against it". These carry S+, allowing
either singular or plural verbs.

Special S links
Ss#t is used for a few nouns that can take "be+that" as
predicates:

	The idea was that we would go to London
	*The vacation was that we could go to London

This is enforced using a special "THb+" connector on forms
of "be"; "THb" then requires an "Ss#t" in post-processing. See
"TH".

Ss#b is used for a few subjects - "it", "this", and "that" -
that can take the predicate "(be) because (clause)": "This is
because he is stupid". See "BI". Ss#q is used for subjects
like "question" that can take the predicate "(be) (indirect
question)": "The question is why he did it". See "BI".

S#x and S##i, along with the link SX, are used to control the
use of the pronoun "I". "I" normally acts like a plural noun
("I run" / "*I runs"), with two exceptions: "I was" / "*I
were", and "I am" / "*I are".  To control this, we simply give
"I" an Sp*i+ connector; we give "are" and "were" an Spx-
connector; and, in post-processing, we outlaw Spxi links. (We
do this by stipulating that an Spxi may not occur in the same
group as any kind of S, thus prohibiting it from coexisting
with itself.) We also give "I" an SX+, and give "was" an SX-,
allowing "I was". "Am", the only uniquely first person verb,
is given an "SX-" as well. (For cases of s-v inversion, we
treat SI and SXI exactly analogously to S and SX.)

Ss#w is used for question-words like "who" that can act as
noun-phrases in subject-type questions: "Who is coming?"
This subscript serves a rather arcane purpose in post-processing.
See "SI: Questions without s-v inversion". S##c is used in
comparatives; see "MV: Comparatives IV".

Ss#g: Gerunds
Ss*g is used for gerunds: "-ing" forms of verbs that act like
nouns or heads of noun phrases.

           +------Ss*g-----+            
           |               |            
	Playing the piano is fun	

This is perhaps a good place for a general discussion of gerunds.

The use of gerunds is extremely problematic. It involves a huge
twilight zone of strings which vary rather gradually in their
grammaticality. There are two basic questions to be answered.
1. What are the rules governing the construction of the
actual gerund phrase? 2. What are the rules governing its
larger context?

First, how can gerunds phrases be constructed? There are
basically two ways: A) with the normal complement of the verb,
and no determiner; or B) with a determiner (and other common
modifiers often used with nouns), but without the normal
complement.  Let us call these the c/nd case and the nc/d
case, respectively.

Gerunds: The Complement / No Determiner Case
Gerunds can be used with their normal complement and no 
determiner:

	Sleeping is fun
        Chasing dogs is fun
	Telling John to leave won't help the situation
	Telling John that you hate him will destroy your relationship
	Graduating from college first will make you more marketable

Whatever requirements apply to the complement as the verb is
normally used apply to the gerund also (but only in the c/nd 
case: the nc/d case is quite different, as described
below). The constraints that make sentences 1, 3, 5 incorrect
make the equivalent gerund phrases incorrect also:

	1.*I talked Jane
	2.*Talking Jane is fun
	3.*I told to do it
	4.*Telling to do it won't help the situation
	5.*I like to chase
	6.?Chasing is fun

(A possible exception is cases like the last one, where the
complement is simply omitted from a verb which otherwise
requires one.  This case will be discussed later.)

(With strain, gerunds may also be used in this way with a
possessive determiner: "Your telling Jane to leave was a
mistake". For this we use DP; see "DP".)

To handle cases such as these, we could directly disjoin Ss*g+
with Pg- on "-ing" forms of verbs (the Pg- is used in present
participles). There is a problem here, however. On present
participles, the complement expression must occur to the right
of the main "Pg- or Mg-" expression. This is because when "B-"
connectors on gerunds are used (which are part of the
complement expression), they may need to hook back beyond the
Pg link:

         +------B------+
         |    +---Pg---+
         |    |        |
	What are you doing

With gerunds, however, the reverse is true: the Ss#g link must link
to the right beyond whatever complement links are made (O, TH,
etc.):
           +------Ss*g--------+
           +-TO-+             |
           |    |             |
	 Trying to kiss Susan was stupid

therefore the entire "Pg" expression must be disjoined with the
entire "Ss*g+" expression. Because of this, it seems clearer simply
to treat the present participle and the gerund as two different
words: the present participles are listed under "trying.v",
"chasing.v"; the gerunds are listed under "trying.g", "chasing.g".
The Ss*g+ expression contains the entire complement of the verb.

So far, then, the usual expression for the ".g" entry for
gerunds is simply:

	[normal complement] & Ss*g+;

Gerunds: The Determiner / No Complement Case
Gerunds may also be used with a determiner.  In this case,
they may not take their normal complements.  The situation
here is complex.

Take a simple transitive verb like "chase". When a determiner is
used, taking a simple direct object is clearly wrong (ex. 1).
Taking no complement sounds questionable (ex. 2). The usual
thing is to take an "of" phrase (ex. 3).

	1.*The chasing dogs is fun
	2.?The chasing is fun
	3.The chasing of dogs is fun 

With intransitive verbs, having no complement sounds funny
also; here again, it's normal for an "of" phrase to be
used. (Notice that with intransitive gerunds, "of X" names the
subject of the verb; with transitive gerunds, "of X" names the
object.)

	4.?The graduating changes the situation	
	5.?The sleeping can ruin a lecture
	6.The graduating of Fred changes the situation	
	7.The sleeping of students can ruin a lecture

How about "complex" verbs - those requiring other complements
such as infinitives or clauses? Here again, straightforward
use of the complement is definitely wrong (ex. 8-11). Use with
no complement is iffy (ex. 12-13), as is use with no
complement (ex. 14-18).

	8.*The telling Jane to leave was stupid
	9.*The showing how to use the program seemed 
		to interest people
	10.*The attempting to go to the party really angered Joe
	11.*The demonstrating that our program 
		could handle complex sentences impressed people

	12.?The telling was unfortunate
	13.?The demonstrating seemed to impress people

	14.?The telling of Jane was stupid
	15.?The showing of the program seemed to impress people
	16.*The attempting of Jane to go angered John
	17.*The telling of Jane to go was stupid
	18.?The demonstrating of our program's abilities 
		impressed people

Sentences like the last five above are perhaps not so much
incorrect as unnecessary; in most cases, we have nouns 
such as "demonstration" and "attempt" which we use instead.

So, when a determiner is present, using the normal complement
is wrong with transitives and complex verbs. Having no
complement sounds doubtful with transitives and complex verbs,
and also with intransitives (where it corresponds to the
normal use of the verb).  Using "of" phrases is fine with
transitives, okay with intransitives, doubtful with complex
verbs. (This means that with some complex verbs that cannot be
transitive, like "wish" and "hope", there is no really good
way of using the gerund with a determiner - which I think is
true.)  For the moment, we ignore most of these subtle
distinctions. We allow any gerund to be used with a
determiner; we allow use with "of" with cost 0 (using OF+); we
allow use without "of" with cost 2; and we disallow any use of
the normal complement.  This yields
	
	(D- & (OF+ or [[()]])) & Ss+;

(Notice that the nc/d usage of gerunds uses an "Ss+" connector
to attach to the rest of the sentence, rather than "Ss*g+";
this is explained below.)  

When gerunds are modified by determiners, they may also be
modified by adjectives, relative clauses, and participle
modifiers. Thus we give them "{@A-}", "{@M+}" and "{R+ &
Bs+}", just like singular nouns. Other determiners may be
used, such as possessives. Singular-only determiners like "a"
cannot be used; gerunds seem to act like mass nouns in this
sense.  Even some mass-noun determiners like "some" and "most"
sound doubtful, but for now we allow them.

	The sleeping of students described by Fred is a big problem
	The sleeping of students I told you about is a big problem
	The insensitive/frequent/habitual sleeping of students 
		is a big problem
	His chasing of the dog didn't help matters
	?Some chasing of dogs will solve the problem
	?Most chasing of dogs is unecessary

This yields:

{@A-} & Dmu- & (OF+ or [[()]]) & {@M+} & {R+ & Bs+...} & Ss+;

Gerund Phrases with Neither Determiner nor Complement
What about gerund phrases with neither a determiner nor a 
complement?

	Running is fun
	?Chasing should be disallowed
	?Telling was a bad idea

With intransitive verbs like "run", such a usage will be
allowed anyway; an "empty" complement is one possible use of
the verb. Even with verbs like "chasing" and "telling",
however, one occasionally sees use of the verb with neither a
determiner or a complement. We therefore allow this with cost
2; we incorporate it into the nc/d expression. The expression
then becomes

{@AN-} & {@A-} & (Dmu- or [[()]]) 
& (OF+ or [[()]]) & {@M+} & {R+ & Bs+...} & Ss+;

Noun-modifiers on Gerunds
Adjectival-noun modifiers of gerunds pose a problem.  One
sometimes sees these used either with a determiner or without.

	Drug running has fueled the economy here for many years
	The drug running here has fueled the economy 
		here for many years
	?Dog chasing is a big problem
	?The dog chasing is a big problem

However, one never sees both a noun-modifier on a 
gerund and a complement:

*Dog chasing cats is a big problem
*Student complaining that the rules are unfair is very common

Therefore, we treat noun-modifiers as part of the nc/d usage
(which, as described above, does allow usage without a
determiner with cost 2).

{@AN-} & {@A-} & (Dmu- or [[()]])
& (OF+ or [[()]]) & {@M+} & {R+ & Bs+...} & Ss+;

Combining the nc/d and the c/nd expressions together yields

([normal complement] & Ss*g+) or
({@AN-} & {@A-} & (Dmu- or [[()]])
& (OF+ or [[()]]) & {@M+} & {R+ & Bs+...} & Ss+);

The Use of Gerunds
So much for the way gerund phrases are constructed. Once a valid
gerund phrase has been constructed, how may it be used?

It may be noted that, in the above sentences, I have used
gerund phrases as subjects connecting to a wide variety of
verbs. There are certainly a large number of verbs that
gerunds can be subjects for, ranging from absolutely clear-cut
cases, to somewhat metaphorical cases, to highly metaphorical
cases. Many verbs which normally refer to actions, which one
would think could not be performed by other actions, are often
used with gerunds. The only kind that are never used with
gerund subjects are those that imply physical actions which
are never used figuratively, and those that imply a state of
mind: e.g. a propositional attitude, emotion, etc..

	Inviting John will cause problems 
	Inviting John may well destroy the party
	Inviting John says to Cathy that you don't like her
	*Inviting John kicked Fred in the pants
	*Inviting John knows that Fred won't come
	*Inviting John hopes that he won't come

There seems to be no good way of limiting these uses,
especially as we do not do so for ordinary nouns (i.e., we
allow "The invitation of John knows/hopes that Fred won't
come").  So, we allow gerunds - both in the nc/d case and the
c/nd case - to make S links to any verb. (Clearly, both types
act as singular nouns, not plurals: "*Inviting John cause
problems.")

As prepositional objects, gerunds can be used quite freely
also. Some prepositions take gerunds extremely freely and
commonly. The nc/d usage sounds acceptable with almost any
preposition; the c/nd usage is extremely common with some
prepositions like "by" and "about", less common with others.

	I caused a problem by inviting John
	?I caused a problem by the inviting of John
	I should have talked to you before inviting John
	?I should have talked to you before the inviting of John
	We had a discussion about inviting John
	We had a discussion about the inviting of John
        ?This led to inviting John
        This led to the inviting of John

However, the c/nd usage has already been handled here in
another way, using Mg (see "M: Mg and Mv used with
Conjunctions").  We need only address the nc/d case
here. (This is another reason for disjoining the nc/d case and
the c/nd case.) Thus we add J- to the nc/d expression:

(([normal complement] or @AN-) & Ss*g+) or 
({@AN-} & {A-} & (Dmu- or [[()]])... & (Ss+ or J-));	

How about ordinary verb objects? Here, the c/nd case usually
sounds quite wrong. There are a few exceptional complex verbs
where it occurs commonly - more with the c/nd usage than the
nc/d usage:

	I hate/enjoy/recommend inviting John
	?I hate/enjoy/recommend the inviting of John to parties

For c/nd cases of this type we use Pg. With most other verbs,
gerunds are used very rarely as objects. It seems that gerunds
are used figuratively less often as objects than they are as
subjects. When they are used, it is more often with the nc/d
usage.

	We completed/defended/fought the inviting of John
	*We completed/defended/fought inviting John	
	We made the inviting of John impossible
	?We made inviting John impossible
	We expected the inviting of John to cause problems
	?We expected inviting John to cause problems
	We gave the inviting of John a thorough discussion
	*We gave inviting John a thorough discussion
	*We kicked/believed/shouted/promised/sold the inviting 
		of John
	*We kicked/believed/shouted/promised/sold inviting John

For the moment, we simply allow all nc/d usages as objects,
and forbid all c/nd usages (except for a few verbs that use
Pg). This yields the following:

(([normal complement] or @AN-) & Ss*g+) or 
({@AN-} & {A-} & (Dmu- or [[()]])... & (Ss+ or J- or O-));		

There are a few gerunds that are used as objects with a
variety of different verbs. Many of these are sports, bodily
functions discussed in medical terms, and activities which are
proscribed or illegal. 

	That portion of the brain controls speaking, 
		reading, and writing
	*The law controls selling cigarettes 
	The disease can cause swelling and itching
	*The recession caused losing jobs 
	The law would prohibit/allow/restrict/affect 
		smoking/fishing in public places
	*The law would prohibit/allow/restrict/affect 
		selling cigarettes / eating fish

The usual usage here is without either a complement or a
determiner. Recall that this usage is covered under the c/nd
usage. Therefore, since we allow gerunds to be used as ordinary
objects under the c/nd usage, these cases will be covered as
well.

"Urfl-only" domains 
One final point about gerunds. In the c/nd usage of gerunds,
the gerund phrase appears to constitute a verb expression
which implies a different subject from the rest of the
sentence. By the logic of post-processing, then, it seems
sensible to include the gerund phrase in its own domain. When
the gerund is acting as a subject, the gerund phrase includes
everything starting from the gerund word and tracing to the
right, underneath (and not tracing through) the Ss#g
link. This domain structure does not correspond either to
normal domains or to "urfl" domains (see "TOo"). Thus we
create a special domain structure especially for this purpose:
"urfl-only".  Ss#g links then start 'd' domains, which are
"urfl-only".

           +--------------Ss*g--------+-----O---+
           +---MVp(d)--+---J(d)--+    |  +---D--+
           +-O(d)-+    |    +D(d)+    |  |   +-A+
           |      |    |    |    |    |  |   |  |
	Telling John about the party was a bad idea

("Urfl" domains include everything "under the root link from
the left", as well as including everything traced from the
word on the right end of the root link, like ordinary
domains. "Urfl-only" domains include only the links that are
under the root link and reachable from the left.)

In the nc/d usage, gerunds seem to act much more like simple
nouns. Therefore there is no need for them to create new
domains. Thus ordinary S+ connectors are used here.