difficulty performance contract and its effect

Theory is a difficult situation where the implementation of a contractual obligation as a result of unforeseen events beyond the control and without physically impossible, difficult and costly to the economy and the balance of the contract is impaired. In such circumstances, the theory difficult to restore the balance of the contract is entered. This is a different legal systems under different titles, such as theory predicts failure, severe and unexpected difficulties are important.. The solution of this system and principles adopted different. Examine the books and determine the best and most fair contracts and the effect of the rules and principles of the theory in this paper will be a tough match.