Linear Combination;
Euclidean Space;
Space Move;
Nonnegative Coefficient;
D O I:
10.1007/PL00009395
中图分类号:
TP301 [理论、方法];
学科分类号:
081202 ;
摘要:
We prove that if some balls in the Euclidean space move continuously in such a way that the distances between their centers decrease, then the volume of their union cannot increase. The proof is based on a formula expressing the derivative of the volume of the union as a linear combination of the derivatives of the distances between the centers with nonnegative coefficients.