The mistake in common system is mainly prescribed in contract law . It is based on the mutual interests balance and transaction safety value and divides mistakes into unilateral mistake mutual and common mistake .

英美法系的错误理论主要规定在合同法中，它建立在双方利益平衡和交易安全价值基础上，将错误划分为 单方 错误，双方错误和共同错误。

A unilateral mistake is one where one of the parties is mistaken and the other party knows of their mistake .

单方 误解是指合同一方产生了误解，而另一方明知对方产生了误解。