ln the paper,the second countability axiom is described from the theory of convergence classes,and in the meantimem,it is obtained a sufficient and necessary for a space to satisfy the second countability axiom.
用收敛类刻划了满足第二可数公理的空间，并得到一个充要条件。
This paper gives the condition of satisfying the first countable principle for the three special topologies on the function space Y X, for special topologies of uniform convergence, compact convergence and Cauchy convergence.
本文给出了函数空间上的一致收敛拓扑、紧收敛拓扑及 Cauchy收敛拓扑满足第一可数公理的条件 。