*** Guide-to-Links ***
P
P is used to link forms of the verb "be" to various words that
can be its complements: prepositions, adjectives, and passive
and progressive participles.

	+S-+Pp-+
        |  |   |
	He is in the yard (Pp)
	He is running (Pg)
	He was chosen (Pv)
	He was angry (Pa)

Some of these link-types, particularly Pg and Pa, are used
also with other verbs that take complements of these kinds.

Forms of "be" have P+, disjoined with a number of other
connectors: O+ ("He is a scientist"), K+ ("He is out"), OF+
("He is of noble birth"), and TO+ ("The idea is to do
it"). (Forms of "be" also may take no complement, with a cost
of 2: "I'm not a doctor, but she is".) Since the subscripted
forms of P+ on be need to be conjoined with other connectors
in different ways, we list them separately in the expressions.

Pp
Pp is used to attach forms of "be" to prepositions.
Prepositions thus have "Pp-" directly disjoined with other
connectors used for attaching prepositional phrases to things
like Mp- (used for phrases modifying nouns), MVp- (used for
phrases modifying verbs), CO+ (used for openers), and so on.

A few other verbs which require prepositional complements (or
some other complement), like "get", "put (+obj)", and "let
(+obj)", also take Pp+.

Pg
Pg connects verbs that take present participles with present 
participles.

            +--Pg--+
	    |      |
	I enjoy running

A number of verbs - "be", "enjoy", "like", "hate", "remember" -
take present participles as possible complements; such verbs
have "Pg+" disjoined with other complement connectors (like
O+, TO+, etc.). A few verbs take both objects and present
participles: "I saw him leaving". Such verbs take "O+ & {Pg+}".

Present participles can also be used with no preceding verb in
so-called participle modifiers: "The dog chasing Jane was
black". Mg is used here, not Pg; this distinction relates to
post-processing (see "Mg"). Present participles can also be
used as subjects ("Playing the piano is fun"); such "gerund"
usages use "Ss*g+" connectors. See "Ss#g".

Pgf is used by post-processing to control the use of "it" and
"there". See "SF: Filler-it".

Pv
Pv is used to connect forms of "be" to passive participles:

	      +-Pv+
              |   |
	John was hit

Forms of "be" have "Pv+" disjoined with their other complement
connectors (O+, Pg+, etc.).

Since the passive form of a verb is always the same as the
past participle form, the same expression can be used for
both: the "Pv-" connector is thus disjoined with the "PP-".
However, the connectors conjoined with Pv- are quite different
from those conjoined with PP-. First of all, only transitive
verbs have Pv- connectors (*"He was arrived").  Moreover, the
Pv- connector must be disjoined with the O+ connector on such
verbs, to prevent "*He was hit the dog".

When verbs take complement connectors such as "TH+", "TO+",
and "QI+", the Pv- must usually be disjoined:

           +--Pv-+
           |     |
	I had known of the problem
	I had known that it was a problem
	I had known what was happening

      *	Jane was known of the problem
      *	Jane was known that it was a problem
      *	Jane was known what was happening

The complication here is that, frequently, such constructions
are permissible when the subject is "it". 

	It was known that it was a problem
	It was known what was happening

We already have a mechanism in post-processing for ensuring
that certain complement connectors ("THi", "QIi") are only
used with "it" as the subject (see "SF: Filler-it"); so these
can be used here. This produces:

	known: (PP- & (O+ or QI+ or TH+ or C+ ....)) or
	       (Pvf- & (QIi+ or THi+...));

(Notice that Pvf is used here. See "SF: Filler-it".)  A
further complication is that sometimes certain complements are
permitted only with the passive, for example: "He was known
to be clever": "*I knew him to be clever". This yields:

	known: (PP- & (O+ or QI+ or TH+ or C+ ....)) or
	       (Pvf- & (QIi+ or THi+ or TO+...));

If a verb can take an object plus another complement, such as
an infinitive (O+ & TOo+) or clause (O+ & TH+), the Pv- must
be disjoined with the O+, conjoined with the other complement
connector:

            +--TOo-+
            +-O-+  |
            |   |  |
	I told him to go
            
            +-Pv+-TO-+
	    |   |    |
	He was told  to go

	*He was told him to go

this yields

	told: (PP- & ((O+ or B-) & {TH+ or QI+ or TOo+...})) or
	      (Pv- & {TH+ or QI+ or TO+});

(Note that for the passive, "TO" is used rather than "TOo". The
function of "TOo" is to indicate to post-processing that a new
subject is in force, by starting a new domain; but with the
passive form, a new subject is not in force. In "He was told
to go", "he" is the implied subject of "go".)

Sometimes one encounters what might be called a "prepositional
passive". In most cases, a passive cannot be constructed out
of a verb+preposition phrase: "I went to the house", "*The
house was gone to"; "I threw a stick at the dog", "*The dog
was thrown a stick at"; "We ate in the park", "*the park was
eaten in". There are a few cases of common verb+preposition
expressions, however, where such passives can be constructed:
"I've been yelled at, gossiped about, lied to, and trifled
with". We simply treat these as idiomatic, non-separable
expressions, similar to passive forms of transitive verbs:

	yelled_at lied_to: Pv- & {@MV+};

Pvf is used by post-processing to control the use of "it" and
"there". See "SF: Filler-it".

Participle Modifiers
In participle modifiers - that is to say, in cases where
the passive participle modifies a noun directly, like
"The dog chased by Fred was black" - Mv is used, not Pv.
See "Mv".

Pa
Pa connects certain verbs to predicative adjectives:

	     +-S--+-Pa-+
	     |    |    |
	The dog was black

Only certain verbs carry Pa+ connectors ("be", "seem", "look",
"taste"). A few carry Pa+ conjoined with O+, such as "make"
and "keep": 

            +---Pa---+
        +-S-+-O-+    |
        |   |   |    |
	I made him happy

A few adjectives can act only as prenominals, not predicatives
("former", "other"); these have only A+ connectors, no Pa-.

Many adjectives can take phrasal complements when used in
predicative position: "She is eager to go", "It is not clear
who will be hired", "I am certain Joe did it", "He is fond of
cookies". On such adjectives, Pa+ is conjoined with TO+, TOi+,
TH+, Ce+, QI+, or OF+ connectors, as appropriate. Pa+ is also
conjoined with @MV+, allowing prepositional or adverbial
modifiers ("She is happy with her job"). In all these cases,
the modifying phrase is optional ("fond" is an exception: "*He
is fond").
        
Paf is used for post-processing, to control the use of
"filler" subjects like "it" and "there". See "SF: Constraints
on Filler-Only Phrases." Regarding Pam, see
"MV: Comparatives II"; regarding Pafc, see "MV: Comparatives
IV".

Pa##j is used for verbs like "make" (mentioned above), which
take object+adjective ("I made him happy"). In such cases, the
adjective applies to the direct object, not the previous
subject; thus a new domain must be started which includes the
O and Pa links but not the S. Pa##j links therefore start "urfl
domains". Pa##j is exactly analagous to TOo and I#j; see "TOo".

Grammar Documentation Page.