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daxiaobing

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zaq123321

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daxiaobing: ½ð±Ò+55, ¡ï¡ï¡ï¡ï¡ï×î¼Ñ´ð°¸, Thank you very much! 2017-12-15 10:50:20
This seems to be related to Jordan curve theorem, which is some kind of basis of ray casting algorithm that is used for detecting whether a point is inside or outside of a closed region.

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2Â¥2017-12-14 17:16:36
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daxiaobing

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ÒýÓûØÌû:
2Â¥: Originally posted by zaq123321 at 2017-12-14 17:16:36
This seems to be related to Jordan curve theorem, which is some kind of basis of ray casting algorithm that is used for detecting whether a point is inside or outside of a closed region.
...

I'm still confused about the condition of the theorem. For example, the inverse function in first quadrant separates the plane in two parts, obviously, a curve connect the two parts must intersect with the inverse function curve( not closed), so I want to ask if the condition can be lower: only require the two parts are open sets, and the curve connect the two parts are continuous?
3Â¥2017-12-15 11:28:57
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zaq123321

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Can you post the theorem and it's proof that you mentioned? I don't understand what do you mean lower condition. Those two parts are one part is bounded and the other part is unbounded

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4Â¥2017-12-15 17:00:17
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daxiaobing

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ÒýÓûØÌû:
4Â¥: Originally posted by zaq123321 at 2017-12-15 17:00:17
Can you post the theorem and it's proof that you mentioned? I don't understand what do you mean lower condition. Those two parts are one part is bounded and the other part is unbounded
...

A is an open set in R^n, A* is the closure of A, and B is the complementary set of A*, C is a curve satisfies: the intersection of C and A is not empty, the intersection of C and B is not empty. Then the intersection of C and the boundary of A is not empty? how to prove it? thank you!
5Â¥2017-12-15 21:06:03
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zaq123321

ר¼Ò¹ËÎÊ (ÖøÃûдÊÖ)

I don't recognize of this kind of proof. You might want to find some standard proof from textbook.

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6Â¥2017-12-15 22:03:15
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daxiaobing

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Ëͺ컨һ¶ä
ÒýÓûØÌû:
6Â¥: Originally posted by zaq123321 at 2017-12-15 22:03:15
I don't recognize of this kind of proof. You might want to find some standard proof from textbook.

Thank you for taking so much time to answer my question£¬your answer helped me a lot.
7Â¥2017-12-15 22:49:10
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