You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: A Survey of XML Tree Patterns 
Chapter Title:  Tree pattern minimization 
1. Abstract of Cited Paper (BIB001):  We consider the problem of minimizing tree pattern queries (TPQ) that arise in XML and in LDAP-style network directories. In [Minimization of Tree Pattern Queries, Proc. ACM SIGMOD Intl. Conf. Management of Data, 2001, pp. 497-508], Amer-Yahia, Cho, Lakshmanan and Srivastava presented an O(n4) algorithm for minimizing TPQs in the absence of integrity constraints (Case 1); n is the number of nodes in the query. Then they considered the problem of minimizing TPQs in the presence of three kinds of integrity constraints: required-child, required-descendant and subtype (Case 2). They presented an O(n6) algorithm for minimizing TPQs in the presence of only required-child and required-descendant constraints (i.e., no subtypes allowed; Case 3). We present O(n2), O(n4) and O(n2) algorithms for minimizing TPQs in these three cases, respectively, based on the concept of graph simulation. We believe that our O(n2) algorithms for Cases 1 and 3 are runtime optimal. 
2. Abstract of Cited Paper (BIB002):  XPath expressions define navigational queries on XML data and are issued on XML documents to select sets of element nodes. Due to the wide use of XPath, which is embedded into several languages for querying and manipulating XML data, the problem of efficiently answering XPath queries has received increasing attention from the research community. As the efficiency of computing the answer of an XPath query depends on its size, replacing XPath expressions with equivalent ones having the smallest size is a crucial issue in this direction. This article investigates the minimization problem for a wide fragment of XPath (namely X Plsr), where the use of the most common operators (child, descendant, wildcard and branching) is allowed with some syntactic restrictions. The examined fragment consists of expressions which have not been specifically studied in the relational setting before: neither are they mere conjunctive queries (as the combination of “//” and “*” enables an implicit form of disjunction to be expressed) nor do they coincide with disjunctive ones (as the latter are more expressive). Three main contributions are provided. The “global minimality” property is shown to hold: the minimization of a given XPath expression can be accomplished by removing pieces of the expression, without having to re-formulate it (as for “general” disjunctive queries). Then, the complexity of the minimization problem is characterized, showing that it is the same as the containment problem. Finally, specific forms of XPath expressions are identified, which can be minimized in polynomial time. 
3. Abstract of Cited Paper (BIB003):  Tree pattern queries (TPQs) provide a natural and easy formalism to query tree-structured XML data, and the efficient processing of such queries has attracted a lot of attention. Since the size of a TPQ is a key determinant of its evaluation cost, recent research has focused on the problem of query minimization using integrity constraints to eliminate redundant query nodes; specifically, TPQ minimization has been studied for the class of forward and subtype constraints (FT-constraints). In this paper, we explore the TPQ minimization problem further for a richer class of FBST-constraints that includes not only FT-constraints but also backward and sibling constraints. By exploiting the properties of minimal queries under FBST-constraints, we propose efficient algorithms to both compute a single minimal query as well as enumerate all minimal queries. In addition, we also develop more efficient minimization algorithms for the previously studied class of FT-constraints. Our experimental study demonstrates the effectiveness and efficiency of query minimization using FBST-constraints.

Literature Review:
The efficiency of TP matching depends a lot on the size of the pattern BIB001 , BIB003 , BIB002 , BIB004 . It is thus essential to identify and eliminate redundant nodes in the pattern and do so as efficiently as possible BIB001 . This process is called TP minimization. All research related to TP minimization is based on a pioneer paper by Amer-Yahia et al. BIB001 , who formulate the problem as follows: given a TP, find an equivalent TP of the smallest size. Formally, given a data tree t and a TP p of size (i.e., number of nodes) n, let S = {p i } be the set of TPs of size n i contained in p (p i ⊆ p and n i ≤ n ∀i). Minimizing p is finding a TP p min ∈ S of size n min such that: Moreover, a set C of integrity constraints (ICs) may be integrated into the problem. There are two forms of ICs: 1) each node of type A (e.g., book) must have a child (respectively, descendant) of type B (e.g., author), denoted A → B (respectively, A ⇒ B); 2) each node of type A (e.g., book) must have a descendant of type C (e.g., name), knowing that C is a descendant of B (e.g, author), i.e., A ⇒ C knowing that B ⇒ C. Since TP minimization relies on the concepts of containment and equivalence, we first detail how containment and equivalence are tested (Section 4.1.1). Then, we review the approaches that address the TP minimization problem without taking ICs into account (Section 4.1.2), and the approaches that do (Section 4.1.3).