Linguistic modality in the context of "Accessibility relation"

Dynamic semantics is a framework in logic and natural language semantics that treats the meaning of a sentence as its potential to update a context. In static semantics, knowing the meaning of a sentence amounts to knowing when it is true; in dynamic semantics, knowing the meaning of a sentence means knowing "the change it brings about in the information state of anyone who accepts the news conveyed by it." In dynamic semantics, sentences are mapped to functions called context change potentials, which take an input context and return an output context. Dynamic semantics was originally developed by Irene Heim and Hans Kamp in 1981 to model anaphora, but has since been applied widely to phenomena including presupposition, plurals, questions, discourse relations, and modality.

In formal semantics and philosophy of language, a definite description is a denoting phrase in the form of "the X" where X is a noun-phrase or a singular common noun. The definite description is proper if X applies to a unique individual or object. For example: "the first person in space" and "the 42nd President of the United States of America" are proper. The definite descriptions "the person in space" and "the Senator from Ohio" are improper because the noun phrase X applies to more than one thing, and the definite descriptions "the first man on Mars" and "the Senator from Washington D.C." are improper because X applies to nothing. Improper descriptions raise some difficult questions about the law of excluded middle, denotation, modality, and mental content.

Deontic modality (abbreviated DEO) is a linguistic modality that indicates how the world ought to be according to certain norms, expectations, speaker desires, etc. In other words, a deontic expression indicates that the state of the world (where 'world' is loosely defined here in terms of the surrounding circumstances) does not meet some standard or ideal, whether that standard be social (such as laws), personal (desires), etc. The sentence containing the deontic modal generally indicates some action that would change the world so that it becomes closer to the standard or ideal.

This category includes the following subcategories:

An auxiliary verb (abbreviated aux) is a verb that adds functional or grammatical meaning to the clause in which it occurs, so as to express tense, aspect, modality, voice, emphasis, etc. Auxiliary verbs usually accompany an infinitive verb or a participle, which respectively provide the main semantic content of the clause. An example is the verb have in the sentence I have finished my lunch. Here, the auxiliary have helps to express the perfect aspect along with the participle, finished. Some sentences contain a chain of two or more auxiliary verbs. Auxiliary verbs are also called helping verbs, helper verbs, or (verbal) auxiliaries. Research has been conducted into split inflection in auxiliary verbs.