This paper presents that the sum of the value register of linear transformation and thenucleus is a full and necessary condition for direct sum, and from which five inductions are obtained.
给出了线性变换的值域与核的和是直和的充要条件，并由此得到五个推论。
Meanwhile, several relational concepts are defined, and the full and necessary condition under which the standard FDs set becomes a minimum cover, and other problems are discussed.
同时，还定义了与它相关的几个概念，讨论了标准FD集f成为最小覆盖的充要条件及其它问题。
应用推荐