In order for a noun phrase to be bound, it must both be coindexed and c-commanded. For instance, a noun phrase “A” is bound if and only if it is c-commanded by another noun phrase “B“. In addition, A and B must be coindexed to one another, demonstrated in the following example: Ai and Bi. (Carnie, 2006, p. 152)
Carnie, A. (2006). Syntax: A generative introduction. John Wiley & Sons.
Lai, I. S. (1998). The grammar and acquisition of Secwepemctsín independent pronouns. [Master’s thesis, The University of British Columbia].