The restriction to the elements of circuits is just the slope of the constitutive relation is bounded, which is much looser than the demands put forward by previously published papers.

• 结果对电路元件的约束，仅要求其成份关系斜率有界即可。这大大放松了目前已有的经典结果中要求电路元件斜率为正的限制，扩展了已有的结果。