Let C be the class of finite nilpotent, solvable, symmetric, simple or semi-simple groups and n be a positive integer. We discuss the following question on group laws: What is the length of the shortest non-trivial law holding for all finite groups from the class C of order less than or equal to n?:Introduction 0 Essentials from group theory 1 The two main tools 1.1 The commutator lemma 1.2 The extension lemma 2 Nilpotent and solvable groups 2.1 Definitions and basic properties 2.2 Short non-trivial words in the derived series of F_2 2.3 Short non-trivial words in the lower central series of F_2 2.4 Laws for finite nilpotent groups 2.5 Laws for finite solvable groups 3 Semi-simple groups 3.1 Definitions and basic facts 3.2 Laws for the symmetric group S_n 3.3 Laws for simple groups 3.4 Laws for finite linear groups 3.5 Returning to semi-simple groups 4 The final conclusion Index Bibliography / Sei C die Klasse der endlichen nilpotenten, auflösbaren, symmetrischen oder halbeinfachen Gruppen und n eine positive ganze Zahl. We diskutieren die folgende Frage über Gruppengesetze: Was ist die Länge des kürzesten nicht-trivialen Gesetzes, das für alle endlichen Gruppen der Klasse C gilt, welche die Ordnung höchstens n haben?:Introduction 0 Essentials from group theory 1 The two main tools 1.1 The commutator lemma 1.2 The extension lemma 2 Nilpotent and solvable groups 2.1 Definitions and basic properties 2.2 Short non-trivial words in the derived series of F_2 2.3 Short non-trivial words in the lower central series of F_2 2.4 Laws for finite nilpotent groups 2.5 Laws for finite solvable groups 3 Semi-simple groups 3.1 Definitions and basic facts 3.2 Laws for the symmetric group S_n 3.3 Laws for simple groups 3.4 Laws for finite linear groups 3.5 Returning to semi-simple groups 4 The final conclusion Index Bibliography

What makes real life contractual arrangements? How does the law influence real life contractual arrangements? These are everyday questions for businesspeople and commercial lawyers. The traditional ‘imperative’ view of law assumes that business people contract ‘in the shadow of the law’ and contractual arrangements conform to what the law says. But empirical studies on contract practice suggest that contract law may, in fact, play a very insignificant role in real life contractual arrangements. This thesis provides a sociological view of the role of contract law in real life contractual arrangements in the context of the Vietnamese market. Specifically, this thesis applies an institutional law & economics approach to investigate how social structures of the market influence contractual arrangements to marginalize contract law in the Vietnamese market. Drawing on two surveys of contract behaviour in the Vietnamese market, this thesis finds that real life contractual arrangements respond to the institutional structure of the market as a whole, rather than only ‘the shadow of the law’. Institutional changes in the Vietnamese market suggest that there exists a merchant law system, constituted of traditional moral norms and social structures in the market. This merchant law system continues to order contractual arrangements in the market, despite the introduction of a transplanted contract law system. Disagreeing with the imperative approach, this thesis claims that contract law reform should conform to the institutional structure of the market to reduce transaction costs of contracting and to provide an effective framework for real life contractual arrangements.