Binding theory

In generative syntax, binding theory is a theory on A-binding.

Comments
Binding theory consists of the three conditions in (i).

(i) A An anaphor is  bound in its  binding domain. B A pronominal is  free in its binding domain. C An R-expression is free.

Usually these conditions are conjoined with a characterization of anaphors, pronominals and R-expressions in terms of the features 'anaphor' and 'pronominal' as in (ii).

(ii) a [+anaphor, -pronominal] =  anaphor b [+anaphor, +pronominal] =   PRO c [-anaphor, -pronominal] =  R-expression d [-anaphor, +pronominal] =  pronominal

Link
Utrecht Lexicon of Linguistics