Structural relations identifies the organization of tree structures (Carnie, 2006, p. 119) Each piece featured combines to form a tree structure and recognize relationships amongst its elements. These components may include Branch, Node, Root Node, Mother, Daughter, Sister and their relations: C-Command, Domination, and Immediate Domination.
Carnie, A. (2006). Syntax: A generative introduction. John Wiley & Sons.