Effects of quenched randomness in statistical mechanics

Rigorous results concerning mathematical models of disordered systems in classical statistical mechanics are presented. They fall into two categories. Results of the first category are general and dimension independent. They concern the order of magnitude of fluctuations of extensive quantity is introduced in extensive quantities; the notion of extensive quantity is introduced in Chapter 2 and plays a central role there. Results of the second category concern absence of certain phase transitions, caused by randomness (the rounding effect). They are more special and apply only in dimensions which are low enough. The proofs are based on probabilistic tools, such as martingales and moment generating functions