At last, a new definition of the rough degree is defined, and lower approximation has the same inequality and the same sufficient condition as upper approximation with the new definition.
最后，给出一个新的粗糙度定义，并证明在这种定义下，下近似具有与上近似一样的不等式及其充分条件。
2
"Inequality has the natural and necessary effect... Of materializing our upper class, vulgarizing our middle class, and brutalizing our lower class" (Matthew Arnold).
This paper discusses the inequality of the upper and lower bounds of the limit analysis of an isotropic plate with equal thickness when it is subjected to the action of various loads.