知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见解，找到自己的解答」为品牌使命。

@turkeyhundt I don't like appealing to "common sense" results like this because it would lead one to believe that negative binomials (for example) aren't a thing due to the factorial function, and yet there …

知乎是一个中文互联网高质量问答社区和创作者聚集的原创内容平台，提供知识共享、互动交流和个人成长机会。

Product of inverse matrices $ (AB)^ {-1}$ Ask Question Asked 12 years, 1 month ago Modified 3 years, 11 months ago Viewed 298k times

6 days ago · CPU天梯图更注重综合性能，只具有参考意义，选择CPU要根据需求选择。 生产力用户更偏重多核性能，可以参考综合性能天梯图 游戏用户更偏重单核性能，综合性能天梯图参考意义不大 桌 …

May 11, 2015 · There are multiple ways of writing out a given complex number, or a number in general. Usually we reduce things to the "simplest" terms for display -- saying $0$ is a lot cleaner than saying …

知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见解，找到自己的解答」为品牌使命。

Jun 13, 2020 · Is there a formal proof for $(-1) \\times (-1) = 1$? It's a fundamental formula not only in arithmetic but also in the whole of math. Is there a proof for it or is it just assumed?

知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见解，找到自己的解答」为品牌使命。

I am struggling to understand what the space $L^1$ is, and what it means for a function to be $L^1$. A friend told me that a function $f$ is $L^1$ if $\int_\mathbb {R} |f|$ is finite.