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标题: 五 块 不 同 颜 色 的 布 料 [打印本页]

作者: 野 菜 花    时间: 2005-4-7 04:30
标题: 五 块 不 同 颜 色 的 布 料

怎 样 裁 剪 缝 制 , 可 使 每 一 块 都 与 另 四 块 相 接 (一 条 缝 线 只 能 连 两 块 )?
www.ddhw.com

 

作者: fzy    时间: 2005-4-7 19:13
标题: 回复:五 块 不 同 颜 色 的 布 料

Put four at four conners, one at the center. Sew them up to form a rectangle. Take one end of the rectangle, turn it around (180°), and sew it up with the opposite side, to form a Mobius Band. (Is this allowed?  Some kind of 3d formation is probably needed. I could not do it on a 2d plane. )
www.ddhw.com

 

作者: 独木桥    时间: 2005-4-7 19:51
标题: 回复:回复:五 块 不 同 颜 色 的 布 料

it is easy to paint 5 colors adjoining each other on the surface of a bike tube,but I am afraid that no one can do it on a plane.(is four color theorem proved?)
www.ddhw.com

 

作者: 怀疑1    时间: 2005-4-7 20:08
标题: It is not about 4-color Theorem, I think.

Some people think the theorem is proven, some mathematicians do not.  Recently I read from somewhere that one group proposed a much simpler human-readable proof. www.ddhw.com
 
As for this problem, it can not be done on a plane because K_5 is not a planar graph.
www.ddhw.com

 

作者: fzy    时间: 2005-4-7 20:33
标题: 回复:回复:回复:五 块 不 同 颜 色 的 布 料

I did not realize that was the 4 color problem. (Where was my brain? )
www.ddhw.com

 

作者: 野 菜 花    时间: 2005-4-7 20:34
标题: Excellent! [@};-][:D)]

  Excellent!





作者: 怀疑1    时间: 2005-4-7 20:56
标题: Well,you can say it. but maybe more related to K_5

  Well,you can say it. but maybe more related to K_5









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