「狹義相對論」會教你如何運算，把你的「一格」翻譯成我的「一格」。
「狹義相對論」關心的另一個主要問題是，眾多個體因果鏈如何互相影響呢？
其中一個核心結論是，任何兩個個體的相互因果影響（causal influence），速度不會高於光速。任何兩條個體因果鏈之間的訊息傳遞（signal transmission），速度最高只能達到光速。
— Me@2011.02.15
2011.02.15 Tuesday (c) All rights reserved by ACHK
Daily Archives: February 15, 2011
Interacts with itself
In 1954, Chen Ning Yang and Robert Mills proposed to generalize these ideas to noncommutative groups. A noncommutative gauge group can describe a field that, unlike the electromagnetic field, interacts with itself. For example, general relativity states that gravitational fields have energy, and special relativity concludes that energy is equivalent to mass. Hence a gravitational field induces a further gravitational field. The nuclear forces also have this self-interacting property.
— Wikipedia on Introduction to gauge theory
2011.02.15 Tuesday ACHK
重新開機
有一個簡單的方法，可以知道程式作者有沒有為程式用者設想：
看看安裝一個程式時，該個程式會不會要求你「重新開機」。
「好程式」和「壞程式」的分別是，
安裝「好程式」時，它不會要求你「重新開機」。
結論是，大部分情況下，不應安裝任何會要求你「重新開機」的程式。
— Me@2011.02.13
2011.02.15 Tuesday (c) All rights reserved by ACHK
Democracy 2
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You can choose whatever name you like for the two types of government. I personally call the type of government which can be removed without violence “democracy”, and the other “tyranny”.
— Karl Popper
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2011.02.15 Tuesday ACHK
Physics Town 