Prototypical prepositions are of (where the governor is the category) and as (where the object is the category):

• the state of Washington [as opposed to the city] 001

• The liberal state of Washington has not been receptive to Trump’s message. 002

• As a liberal state, Washington has not been receptive to Trump’s message. 003

• I like Bob as a colleague. [but not as a friend] 004

• What a gem of a restaurant! [exclamative idiom: both NPs are indefinite] 005

• the problem/task/hassle of raising money 006

• the age of eight 007

• They did a great job of cleaning my windows. 008

• Topic↝Identity, with a governing noun in the domain of communication or cognition:

  • the topic/issue/question of semantics 009

  • the idea of raising money 010

Something may be specified with a category in order to disambiguate it #001, or to provide an interpretation or frame of reference with which that entity is to be considered. In some cases, like #009, the category is a shell noun (Schmid, 2000) requiring further specification.

Categorizations may be situational rather than permanent/definitional:

• She appears as Ophelia in Hamlet. 011

• He is usually a bartender, but today he is working as a waiter. 012

Paraphrase test: “(thing) IS (category) [in the context of the event]”: “Washington is a liberal state”, “opening a new business is a hassle”, “She is Ophelia”, etc. Note that as+category may attach syntactically to a verb, as in #004 and #011, rather than being governed by the item it describes.

If the object of the preposition is a property (as opposed to a category), the scene role is Characteristic:

• Adnominal: Characteristic↝Identity

  • a car of high quality 013

  • a man of honor 014

  • a business of that sort [contrast with Species] 015

• Secondary predicate adjective: Characteristic↝Identity

  • She described him as sad. 016

  • He strikes me as sad. 017

See also: ComparisonRef