Plan: pronoun

Binding theory and antecedents
The use of pronouns often involves anaphora, where the meaning of the pronoun is dependent on another referential element. The referent of the pronoun is often the same as that of a preceding (or sometimes following) noun phrase, called the antecedent of the pronoun. The grammatical behavior of certain types of pronouns, and in particular their possible relationship with their antecedents, has been the focus of studies in binding, notably in the Chomskyan government and binding theory. In this binding context, reflexive and reciprocal pronouns in English (such as himself and each other) are referred to as anaphors (in a specialized restricted sense) rather than as pronominal elements. Under binding theory, specific principles apply to different sets of pronouns.
In English, reflexive and reciprocal pronouns must adhere to Principle A: an anaphor (reflexive or reciprocal, such as "each other") must be bound in its governing category (roughly, the clause). Therefore, in syntactic structure it must be lower in structure (it must have an antecedent) and have a direct relationship with its referent. This is called a C-command relationship. For instance, we see that John cut himself is grammatical, but Himself cut John is not, despite having identical arguments, since himself, the reflexive, must be lower in structure to John, its referent. Additionally, we see examples like John said that Mary cut himself are not grammatical because there is an intermediary noun, Mary, that disallows the two referents from having a direct relationship.
Example pronoun structure. Since "him" is immediately dominated by "John", Principle B is violated.
On the other hand, personal pronouns (such as him or them) must adhere to Principle B: a pronoun must be free (i.e., not bound) within its governing category (roughly, the clause). This means that although the pronouns can have a referent, they cannot have a direct relationship with the referent where the referent selects the pronoun. For instance, John said Mary cut him is grammatical because the two co-referents, John and him are separated structurally by Mary. This is why a sentence like John cut him where him refers to John is ungrammatical.
The type of binding that applies to subsets of pronouns varies cross-linguistically. For instance, in German linguistics, pronouns can be split into two distinct categories — personal pronouns and d-pronouns. Although personal pronouns act identically to English personal pronouns (i.e. follow Principle B), d-pronouns follow yet another principle, Principle C, and function similarly to nouns in that they cannot have a direct relationship to an antecedent.[9]
Antecedents
The following sentences give examples of particular types of pronouns used with antecedents:
Third-person personal pronouns:
That poor man looks as if he needs a new coat. (the noun phrase that poor man is the antecedent of he)
Julia arrived yesterday. I met her at the station. (Julia is the antecedent of her)
When they saw us, the lions began roaring (the lions is the antecedent of they; as it comes after the pronoun it may be called a postcedent)
Other personal pronouns in some circumstances:
Terry and I were hoping no one would find us. (Terry and I is the antecedent of us)
You and Alice can come if you like. (you and Alice is the antecedent of the second – plural – you)
Reflexive and reciprocal pronouns:
Jack hurt himself. (Jack is the antecedent of himself)
We were teasing each other. (we is the antecedent of each other)
Relative pronouns:
The woman who looked at you is my sister. (the woman is the antecedent of who)
Some other types, such as indefinite pronouns, are usually used without antecedents. Relative pronouns are used without antecedents in free relative clauses. Even third-person personal pronouns are sometimes used without antecedents ("unprecursed") – this applies to special uses such as dummy pronouns and generic they, as well as cases where the referent is implied by the context.