There are restrictions on what type of systems these techniques can be applied to, e.g., these reduction techniques do not apply to systems that are nonholonomically constrained. 这些约化方法在其可应用的系统类型上有一定的局限性，比如其不能应用于不完整约束系统等。
There are restrictions on what type of systems these techniques can be applied to, e.g., these reduction techniques do not apply to systems that are nonholonomically constrained. 这些约化方法在其可应用的系统类型上有一定的局限性，比如其不能应用于不完整约束系统等。
