Gee Law’s Blog

在 Windows 下用命令解压缩 ZIP 文件夹

姚栋想要知道如何在 Windows 中使用命令解压缩 ZIP 文件夹。他表示如果要用 .NET Framework 提供的 API,则需要 4.5,但环境要求 4.0;如果用 PowerShell Expand-Archive 命令,则需要 5.1,但环境只允许 2.0;想用 cmd,但不知道怎么做。然而应该时刻记住:Windows 自带的 GUI 实际上经常是 COM 的图形版,在 COM 中寻找几乎总是可以找到你想要的图形操作的命令版本。

Is the pattern you found persuasive?

Starting from the classic puzzles of finding patterns in a sequence, this entry explores the framework to define persuasive patterns. The framework is found to be quite self-contained in the sense that it is ‘asymptotically invariant’ to the choice of ‘language of expression’. The only short-coming of this framework is that it works only for computable sequences, yet the process of pattern discovery is incomputable.

Is the pattern you found persuasive?

Of elementary general terms

In this entry, I discuss a pathological construction of general terms of a class of integer-valued sequences with the widely accepted concept of ‘elementary functions’. The idea here is to simply ‘concatenate’ the integers in a real number, then extract the appropriate digits for each term. It turns out that this definition characterises the elementariness very well (note that the definition is also self-referencing). The extended inspection leaves a problem open: Are all integer-valued sequences elementary? Update: The question is solved with an affirmative answer.

Mean value theorem and heuristics from differential equation

In this entry, I discuss a kind of widely posed exam problems for elementary calculus learners. It concerns a technique of application of (differential) mean value theorems. Speficially, a class of such problems can be solved dogmatically if the equation to prove resembles a ‘factorisable’ linear differential equation.

Mean value theorem and heuristics from differential equation

Discount aux Galeries Lafayette and NP-completeness

I allowed myself some CHANEL products to ‘reward’ myself for the acceptance of my first cryptography paper. I also consider spending money at its best value an interesting game. A commonly-seen discount aux Galeries Lafayette Xidan (Beijing) leads to an obviously NP-complete problem. Haha!

Discount aux Galeries Lafayette and NP-completeness

随机过程习题课见闻二则

去听习题课并不是为了听讲习题,而是为了混参与分数(虽然我相信这个课不用参与分数也可以拿很高的分)。虽然,仍然有两则有趣的见闻以飨观众。