In the past years，all Concepts in graphs were translated to hypergraphs，in special，the definition of cycles in hypergraphs is the same as in graphs．As extension oFgraphs，there are many results Oil trees，cycles，covering and coloring of hypergraphs．

Chapter 1 Basic Terminologies

Chapter 2 Relational Databases

 2．1 Operators and operands in relational algebra

 2．2 Dependences in relations

 2．3 Entropy

 2．4 Conflict—free sets of MVDs

 2．5 Consistency of databases

 2．6 Monotone join expression

Chapter 3 Some Classical Results

Chapter 4 Acyclic Hypergraphs

 4．1 Characteristics of acyclic hypergraphs

 4．2 Size of acyclic hypergraphs

 4．3 Enumeration of acyclic hypergraphs

Chapter 5 Algorithms to Test Acyclicity of Hypergraphs

Chapter 6 Characteristics of Cyclic Hypergraphs

Chapter 7 Three Parameters

Chapter 8 Cycles of Hypergraphs

 8．1 Cycle—axiom of hypergraphs

 8．2 Cyclomatic numbers of hypergraphs

 8．3 Extreme value of cyclomatic numbers of hypergraphs

 8．4 On size ofunicycle hypergraphs

 8．5 M5bius functions

Chapter 9 Hamiltonian Cycles of Hypergraphs

Chapter 10 Decompositions of Hypergraphs

 10．1 Acyclic decompositions of hypergraphs

 10．2 A structure decompositions for hypergraphs

Bibliography

Appendix