Slow, continuous change may be the norm during periods of environmental stability, while rapid evolution of new species occurs during periods of environment stress.
缓慢的、持续的变化可能是环境稳定时期的常态，而新物种的快速进化发生在环境压力时期。
2
In this paper the properties and fixed point theorems of completely continuous maps on denumerable norm Spaces are studied.
本文讨论可数模空间上全连续算子的有限维逼近定理及该空间的一些性质。
3
The result derived extends persistence of norm continuity of linear strongly continuous semigroups and enriches theory of semigroups of nonlinear operators.