24小时热门版块排行榜    

查看: 701  |  回复: 4
当前只显示满足指定条件的回帖,点击这里查看本话题的所有回帖

hzsh2009

铜虫 (小有名气)

[求助] 关于subgroup的证明

let H be a subgroup of order 2 in G.
Show that NG(H)= CG(H).  即normalzier和centralizer相等
Deduce that if NG(H)=G then H<=Z(G)
回复此楼
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

zhencai688

新虫 (小有名气)

引用回帖:
4楼: Originally posted by zhencai688 at 2011-10-10 10:21:52:
Since N(G)/C(G)=Aut(Z2)=1,  N(G)=C(G).

Since NG(H)/CG(H)=Aut(H)=1,  NG(H)=CG(H).
5楼2011-10-10 10:25:37
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
查看全部 5 个回答

sdlmm

银虫 (初入文坛)

【答案】应助回帖

★ ★
soliton923(金币+2): 鼓励参与讨论! 2011-09-28 22:58:01
hzsh2009(金币+10): 2011-09-29 05:18:43
Suppose H={e,y} be the order 2 subgp, then first easily we have C(H)<=N(H).Conversly, we have that for any x in N(H), xH=Hx={x, xy}={x,yx}, so we get xy=yx, i.e., x is in C(H). This implies that C(H)=N(H).
As to the second question, if N(H)=G, then this implies C(H)=G by the proof above, i.e., any element in G is commutative with y, that is y is in the center of G, this ends the proof.
2楼2011-09-28 13:34:25
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

zhencai688

新虫 (小有名气)

soliton923: 您也可以写一个出来试一试哈~~^_^ 2011-09-28 22:58:29
引用回帖:
2楼: Originally posted by sdlmm at 2011-09-28 13:34:25:
Suppose H={e,y} be the order 2 subgp, then first easily we have C(H)<=N(H).Conversly, we have that for any x in N(H), xH=Hx={x, xy}={x,yx}, so we get xy=yx, i.e., x is in C(H). This implies that ...

证明的不错  方法很基本但很简练!
3楼2011-09-28 21:17:34
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

zhencai688

新虫 (小有名气)


小雨萌萌(金币+1): 谢谢关注~ 2011-10-11 10:33:53
引用回帖:
3楼: Originally posted by zhencai688 at 2011-09-28 21:17:34:
证明的不错  方法很基本但很简练!

Since N(G)/C(G)=Aut(Z2)=1,  N(G)=C(G).
4楼2011-10-10 10:21:52
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
最具人气热帖推荐 [查看全部] 作者 回/看 最后发表
[考博] 售SCI文章,我:8O.5.5.1O.54,科目全,可十急 +4 k0dTPqJtl0jt 2026-08-14 5/250 2026-08-15 04:45 by 4wMiSEwB6436
[基金申请] 小木虫上这么多卖论文的,真有人买论文么?感觉没必要啊 +11 Tide man 2026-08-10 12/600 2026-08-15 02:12 by home3163
[教师之家] 售SCI一区T0P文章,我:8O.55.1.O.5.4,科目齐全,可+急 +4 7lpolszZVXgi 2026-08-14 4/200 2026-08-15 01:08 by 4wMiSEwB6436
[论文投稿] 售SCI一区文章,我:8O5.5.1.O5.4,科目全,可伽急 +3 HFw0lei2R37i 2026-08-14 5/250 2026-08-15 00:16 by 4wMiSEwB6436
[考研] 售SCI一区T0P文章,我:8.O.55.1.O.54,科目齐全,可+急 +4 HFw0lei2R37i 2026-08-14 8/400 2026-08-15 00:16 by 4wMiSEwB6436
[基金申请] 欢迎发来filecode的Mz6后的代码验证其规律 +23 医学老男孩 2026-08-13 49/2450 2026-08-14 20:02 by zhaifei
[基金申请] 哪位老哥知道今年的国自然具体哪一天放榜? +5 Ldrop2023 2026-08-13 5/250 2026-08-14 18:48 by ssxclkj
[硕博家园] 读博的好处 +4 lnee 2026-08-11 4/200 2026-08-14 10:20 by ahsoarli
[基金申请] filecode +15 documentary 2026-08-10 17/850 2026-08-14 10:08 by kissu88
[基金申请] FileCode能看出啥? +10 要乐观耀哥 2026-08-10 32/1600 2026-08-14 09:37 by 要乐观耀哥
[基金申请] 关于Filecode分析方法 +9 majunge000 2026-08-10 12/600 2026-08-13 23:20 by iwuli
[文学芳草园] 阿姨 +4 汪汪锅 2026-08-09 4/200 2026-08-13 19:43 by arzu_hma
[基金申请] 静等基金结果 +8 gjjjzhong 2026-08-10 21/1050 2026-08-13 17:56 by 且听虎啸
[基金申请] 分享一下我之前已中青C的计划书的filecode +4 布布和一二 2026-08-11 5/250 2026-08-13 12:56 by cratir
[基金申请] 结合人工智能,周易传统文化,filecode打分制来了,3分以上希望很大。 +3 Tide man 2026-08-12 4/200 2026-08-13 08:35 by ZJTJZ
[基金申请] 什么时候出结果,有咨询渠道??? +3 Tide man 2026-08-11 3/150 2026-08-11 17:54 by kudofaye
[基金申请] 国自然结果 +4 Vierhys 2026-08-10 8/400 2026-08-10 15:06 by Vierhys
[基金申请] 2026国自然放榜时间 +9 布布和一二 2026-08-08 9/450 2026-08-10 11:22 by xxxx2020
[基金申请] 面上项目filecode邪修 +5 西山十月 2026-08-09 7/350 2026-08-10 07:32 by 仁砚薪传
[基金申请] 关于filecode,很负责任的告诉大家 +6 爱看书的可乐 2026-08-08 7/350 2026-08-08 22:13 by a_niu
信息提示
请填处理意见