*** 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: prepositions

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: present participles

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 that act as modifiers on verbs use the "MVg" link: "He swam, leaving a wake". Such modifiers conventionally are preceeded by a comma, as in this example.

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: passive participles

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: predicative adjectives

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".

Conjunctions:

Currently, the Pa link does not work well with conjunctions. Consider: 
      I'd make the pages smaller and the magazine thicker
Planarity of links implies that its the pages that get smaller, and not the making.

Grammar Documentation Page.