educational clip( don't come in if you are not interested in maths or science)

MATTHEW194

people always say space is infinity and has no end. but how do you define infinite? in this clip i just want to show you guys how little you know about infinity

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barying

希爾伯特旅館悖論
http://zh.wikipedia.org/zh-hk/%E ... 6%E6%82%96%E8%AE%BA
由於希爾伯特的這一悖論違反了我們的直覺，因而經常被用於反對實無窮的存在，
如美國哲學家威廉·萊恩·柯萊格（William Lane Craig）就曾這樣來證明上帝的存在：
儘管在數學上這種旅館（或任何無限的事物）並非是不可能的，
但從直覺上這樣的事物永遠不可能存在，
不僅如此，任何實無窮都不可能存在。
如果一個時間序列能夠無限地回退到過去那就會建立起一個實無窮，
既然實無窮不存在，那時間就必然有個「起點」。
每個事物都有其發生的原因，而時間起始的原因不可能是其他事物，只能是上帝。

還找到一個直覺解釋：
問：假設有n個客人，新來一個，房間也是n間，但總有一個人住不下，那第n+1個客人怎麼解釋？
答：這是一個關於無限數集的例子，n這個具體數字是不能代表無限的。
因為數字是無限的，所以是可以成立的，無限的概念就是無窮大。
正如希爾伯特旅館，房子是無限的，可以住下無限個客人。
你可以這樣想，當房子住滿了，來了一位客人，怎麼辦？
叫1號房的可以去2號房，空出1號房給新客人入出。
然後叫2號房的去3號房，給原來的1號房入住，如此一直下去。
你可能會有疑問，這樣總有一個人住不下啊？
其實不是這樣的，因為是無限的房間，所以每人只需搬一次房間，就輪到下一個搬。
這樣一直循環下去，每個時刻都有1個人在搬房間，
那個人就是當時沒住下的人，但是下一刻他就可以住下了，無限循環下去。
問題就解決了，因為人人都有得住，只不過要搬一下房間而已。

MATTHEW194

回復 barying #2 的帖子

thx for that, ching. hehe, seems like no one really interested in this.

barying

MATTHEW194 發表於 2012-10-20 11:06
回復 barying #2 的帖子

thx for that, ching. hehe, seems like no one really interested in this.  ...

It doesn't matter, We must diversify our life.

MATTHEW194

barying 發表於 2012-10-21 04:56
It doesn't matter, We must diversify our life.

sorry, i am just being curious. what do you do for living ching.

barying

MATTHEW194 發表於 2012-10-21 14:18
sorry, i am just being curious. what do you do for living ching.

Not specific, I'll do whatever I interests.

Or you asking my job?

MATTHEW194

barying 發表於 2012-10-21 21:24
Not specific, I'll do whatever I interests.

Or you asking my job?

obviously i am asking about your job.

barying

MATTHEW194 發表於 2012-10-22 01:54
obviously i am asking about your job.

Sorry for my misunderstanding,

I am the manager at a hospitality Group.

MATTHEW194

barying 發表於 2012-10-22 04:10
Sorry for my misunderstanding,

I am the manager at a hospitality Group.

oh ok, so we are both in the health science field.

barying

回復 MATTHEW194 #9 的帖子

Are you long stay in XXX?

or studying?  

MATTHEW194

barying 發表於 2012-10-22 04:25
回復 MATTHEW194 #9 的帖子

Are you long stay in XXX?

how do you know i am from XXX?
well, i got my passport last year( i was a pr), but i am planning to go back to hk after college.

barying

回復 MATTHEW194 #11 的帖子

Don't forgot I'm the forum manager here too.

If you don't want me to location where you are, I can change my words.

By the way, what is "pr".

MATTHEW194

barying 發表於 2012-10-22 04:34
回復 MATTHEW194 #11 的帖子

Don't forgot I'm the forum manager here too.

pr (permanent residency) http://en.wikipedia.org/wiki/Australian_permanent_resident
you gotta live there for 5 years in order for you to get a passport.

barying

回復 MATTHEW194 #13 的帖子

Nice to see you here, Matthew.

I look forward to see more of you share soon.