In its function as infinitive marker, [p en/to] is not generally considered to be a preposition.
Nevertheless, we consider all uses of [p en/to] for adposition supersense annotation because infinitive clauses (infinitivals) can express similar semantic relations as prepositional phrases. 

## Infinitival varieties of [ss Purpose]

Most notably, infinitival purpose adjuncts alternate with [p en/for]-PP purpose adjuncts:

- [ss Purpose]:
	- [ex 001 "Open the door [p en/to Purpose] let in some air."]

	- [ex 002 "Open the door [p en/for Purpose] some air."]

	- [ex 003 "I flew to headquarters [p en/to Purpose] meet with the principals."]

	- [ex 004 "I flew to headquarters [p en/for Purpose] a meeting with the principals."]

Thus, from a practical point of view, we might as well treat infinitival [p en/to] as capable of marking a [ss Purpose].

The following list summarizes semantic analyses that we consider for infinitivals, which are detailed under [ss Purpose]:

###1. **Purpose adjuncts**, whether are adverbial or adnominal. These are labeled [ss Purpose]. Some can be paraphrased with [p en/in_order_to].

###2. In a **commercial scene**, a service to performed in exchange for payment; labeled [ss Theme--Purpose].
Repeated from the discussion under [ss Theme]:

- [ex 005 "They asked $500 [p en/to Theme--Purpose] make the repairs. ([ss Theme--Purpose])"]

- [ex 006 "$500 [p en/to Theme--Purpose] make the repairs was excessive. ([ss Theme--Purpose])"]

###3. **Result** infinitives, such as those in [exref 011 Goal], are labeled [ss Goal].

###4. Constructions of **sufficiency and excess**—*too short [p en/to ComparisonRef--Purpose] ride*, *not tall enough [p en/to ComparisonRef--Purpose] ride*, etc., where the assertion of sufficiency or excess licenses an infinitival—are labeled [ss ComparisonRef--Purpose] or [ss ComparisonRef--Goal]. 
See discussions at [ss ComparisonRef] and [ss Purpose].

The non-semantic label [ss `i] applies to all other uses of the infinitive.

## Infinitival with [p en/for]-subject

In [exref 001 "Infinitive Clauses"], the infinitive clause has no local subject—rather, an argument of the matrix clause doubles as the subject of the infinitive clause (control). However, a separate subject can be introduced with [p en/for], in which case [p en/for]+NP is treated as a dependent of the infinitive verb and labeled [ss `i]:

- [ex 007 "I opened the door [[p en/for]<sub>[ss `i]</sub> Steve [p en/to]<sub>[ss Purpose]</sub> take out the trash]."]

- [ex 008 "It cost $500 [[p en/for]<sub>[ss `i]</sub> the mechanic [p en/to]<sub>[ss Theme--Purpose]</sub> make the repairs]."]

## [p en/for_to] infinitives

These occur in some English dialects: [*for to* infinitives](https://ygdp.yale.edu/phenomena/for-to-infinitives)


## Other infinitivals

Examples of infinitival tokens that do not receive a semantic label appear in [ss `i].