# 米米的博客

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Seen here is the Norwich City Council’s first computer, being delivered to the City Treasurer’s Department in Bethel Street, Norwich in 1957. The City of Norwich, and its forward-thinking Treasurer, Mr A.J. Barnard, were pioneers in the application of computer technology to the work of UK local authorities and businesses. In 1953-4, Mr Barnard and his team began looking for an electronic system to handle its rates and payroll. They began discussions with Elliott Brothers of London in 1955, and the City Council ordered the first Elliott 405 computer from them in January 1956. It was delivered to City Hall in February 1957 and became operational in April 1957. The event was celebrated by a demonstration of the machine in front of the Lord Mayor of Norwich and the press on 3 April 1957. (Norfolk Record Office, ACC 2005/170)

Below is a picture of the new \$5 Raspberry Pi Zero at the same location. The Raspberry Pi is a tiny and affordable computer, designed and built in the UK, that you can use to learn programming through fun, practical projects. I own 2 older models.

Wonders never cease.

2019 年 8 月，Hexo 的 NexT 主题正式加入 PJAX 功能。最初的 PR 一共包含 35 个 commit，约 600 行代码改动。不过这个数字有些夸张，其中约有 200 行是在适配 PJAX 过程中，发现一些插件对于 PJAX 不友好，顺手修改了。此后根据收到的用户反馈，又用了不下十个 PR，修复了 PJAX 中全部已知问题。

## 自洽性

• 在每次 PJAX 刷新后，根据情况「点击」其中一个按钮，确保侧边栏显示正确；
• 将控制显示的 className 移动到刷新区域外，例如设置为 <body>className

## 重新加载脚本

1. 在每个页面中都存在，但只需要加载一次，重复加载反而有可能导致问题（例如音乐播放器，看板娘，背景动画等）
2. 在每个页面中都存在，并且 PJAX 刷新时需要重新加载（例如访问量统计，FancyBox 等）
3. 仅在部分页面中存在，不使用时没有必要加载（例如 MathJax，网站评论区等）

### 第一类脚本

• 不使用匿名函数作为回调函数，而是将其封装，通过 function 进行声明，然后将其作为 addEventListener 的参数，这可以保证其只触发一次；
• 或者在必要时使用 removeEventListener

### 第三类脚本

• 如果用户通过 PJAX 浏览的页面中，都不包含数学公式，那么无需加载 MathJax，减少网络请求；
• 如果用户浏览到了第一个包含数学公式的页面，那么需要加载 MathJax；
• 在此后用户浏览的所有页面中，如果包含数学公式，那么只需要调用以下方法，重新进行渲染

## 总结

Proof by intimidation Trivial!

Proof by cumbersome notation The theorem follows immediately from the fact that when .

Proof by inaccessible literature The theorem is an easy corollary of a result proven in a hand-written note handed out during a lecture by the Yugoslavian Mathematical Society in 1973.

Proof by ghost reference The proof my be found on page 478 in a textbook which turns out to have 396 pages.

Circular argument Proposition 5.18 in [BL] is an easy corollary of Theorem 7.18 in [C], which is again based on Corollary 2.14 in [K]. This, on the other hand, is derived with reference to Proposition 5.18 in [BL].

Proof by authority My good colleague Andrew said he thought he might have come up with a proof of this a few years ago...

Internet reference For those interested, the result is shown on the web page of this book. Which unfortunately doesn't exist any more.

Proof by avoidance Chapter 3: The proof of this is delayed until Chapter 7 when we have developed the theory even further.
Chapter 7: To make things easy, we only prove it for the case , but the general case in handled in Appendix C.
Appendix C: The formal proof is beyond the scope of this book, but of course, our intuition knows this to be true.