Chvatel 博物馆定理

constant · 发表于 2005-10-31 17:25:12

难度：+++

一个 n 边形的博物馆要布置警卫。这些警卫不能随意走动，但可以转动。

1。证明最多 [n/3] 个警卫就可以同时看到博物馆的所有角落。

2。对任意 n >= 3, 证明存在一个 n 边形，使得少于 [n/3] 个警卫不能同时看到博物馆的所有角落。

本报 · 发表于 2009-7-12 12:12:48

http://img21.imageshack.us/img21/5241/dsc06482t.jpg

啊 · 发表于 2007-2-9 13:07:01

Did you use TCN's

husonghu · 发表于 2005-11-10 08:48:53

没关系

我觉得这样也蛮好：激励大家多浏览一点。有兴趣者自会看。我也多赚钱哪！

constant · 发表于 2005-11-10 06:23:41

不好意思，让hu兄擦桌子

husonghu · 发表于 2005-11-10 03:10:22

此题标准答案已由constant给出。有兴趣者请见坛上另贴。

constant · 发表于 2005-11-1 02:05:43

Cool

, And thanks

constant · 发表于 2005-11-1 02:03:57

是这样吗？这个是问题2的一般解。

www.ddhw.com

野菜花 · 发表于 2005-11-1 01:46:20

Thanks both of you for your helps!!

野菜花 · 发表于 2005-11-1 01:20:38

I think at first I saved my graphs in Paint with wrong type ( 24-bit Bitmap), it should be saved in jpg or jpeg types(JPEG File Interchange Format).

Then

1. click 免费上传图片、音频、视频等文件，请点击这里,

2 click 上传图片, then from your browse find your file, and click 开始上传. a URL address will appear. Copy it.

3. Go back to 发贴处, 在 插入内容 处选择图片，paste URL address, click 插入, you picture will be there!

constant · 发表于 2005-11-1 00:53:10

怎么弄的？也教教我

野菜花 · 发表于 2005-11-1 00:47:49

野菜花 · 发表于 2005-11-1 00:32:43

I tried "imageshack.us", I can see my graphs there, but after I coped the URL there and and paste it here, either showed a small window with a red cross inside or a picture from imageshack telling me the type of my picture was not right or even nothing.

I also tried "免费上传图片、音频、视频等文件，请点击这里"?...

I can copy and paste them in word, but connot paste them here, only appear a lot strange symbols, I read the post 新用户 taught Sea MM how to change to ...and tried to follow his instructions, failed again.

I think it is an important method I should learn, that is why I tried so hard.

ob · 发表于 2005-11-1 00:19:02

http://www.topchinesenews.com/listo.aspx?topic_id=9&msg_id=4004&level_string=0&page=4

husonghu · 发表于 2005-11-1 00:15:28

This should be easy to use, although I haven't try yet.

Please read the instructions, and try to use it.

野菜花 · 发表于 2005-11-1 00:01:31

For question2, I have drawn 6 graphs: from n=6 to n=11, the rest can be easily defined inductively. But I spent a lot time on learning to send the graphs( I drew them through "paint"), and I still failed.

Let me try to describe the shapes of the graphs:

n=6 象空心字母Z，不过两头是尖的

n=9 象这个空心字母Z背上接一个三角瓶(大底向外)

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Chvatel 博物馆定理

回复：Did you use TCN's "免费上传图片、音频、视频等文件，请点击这里"?...

回复：回复：Did you use TCN's "免费上传图片、音频、视频等文件，请点击这里"?..

没关系[:)]我觉得这样也蛮好：激励大家多浏览一点。有兴趣者自会看。我也多赚钱哪！

不好意思，让hu兄擦桌子 [:>][:>]

此题标准答案已由constant给出。有兴趣者请见坛上另贴。

Cool [:B], And thanks

试试（图）

Thanks both of you for your helps!![>:D<][@};-]

回复：怎么弄的？也教教我

怎么弄的？也教教我

I finally send the graphs successfully! [:B][:))]（图）

回复：Did you use TCN's "免费上传图片、音频、视频等文件，请点击这里"?...

Read this one[:)]

Did you use TCN's "免费上传图片、音频、视频等文件，请点击这里"?...

我试了几个小时贴图还是失败了[:((][:((][:((]