<正> The problem of determining the automorphisms of the linear groupsand the possible isomerphisms between them was first studied by O,Schreier and v.d.Waerden[1].They determined the automerphisms ofthe projective special linear group PSL_n(K)for n>1 over a commuta-tive field K and all the possible isomorphisms between them.Then oneof the authors determined the automorphisms of the symplectic group by
<正> 一、引言如我们有一集正整数 S,史奈若曼氐[1]令 S 的密度为分数 S_x~((x)当x=1,2,3,…时之最大下界,就中 S(x)为 S 中不大于 x 之元的个数.设 S 与T 为两个正整数集,我们令 S+T 为 S 内之诸元 s,T 内诸元 t 及所有和数s+t 所组成之集.满氏[2]曾证明:如 S,及 T 的密度相应为σ与τσ+τ≤1时,则 S+T 的密度必不小于σ+τ,且若σ+τ≥1则 S+T 的密度恒等于1.
