This paper deals with some properties of total sub-semigroups of Abelian groups.
研究可换群的完整子半群的性质，并进一步讨论其扩张问题，得出若干结论。
Based on this we raise the bridge problem and the weighted bridge problem, and successfully transfrom these two problems into the restricted sorting problem and weighted restricted sorting problem respectively.
本文定义了一类特殊平面图形G（ω）和规则f，提出了“桥”问题和赋权桥问题把这两类问题分别转化为限制整序问题和赋权限制整序问题并提出相应算法。