这周换一个方法记录blog，以记录自己想记录的东西为主。

在language的大集合里，有一部分语言被作为regular languages，测试他们是否是regular languages的方法是使用DFA & NFA & RL，pumpling lemma得出了有一部分语言是unregular的，unregular的语言不可以用DFA NFA Regular expression去define。这是就需要Grammar（content free grammar） which可以define regular languages and unregular languages

Content-free Grammar

G = (V, A, S, P)
V is a set of variables.
A is constant, terminates 阿尔法贝塔
S is a variable, state symoble
P is a set of rules (production) eg: x -> a a属于(VUA)^* 类似转移方程？
都是有限集
S –> aSb content-free意味着ab对S没有影响
L(G) = {w|wEA*, s->w}

还没整明白，内容转自吴雨森的CSDN。
INT201 决策，计算，语言 笔记

This’s the note of INT201 Week4.
This week will focus on 正则语言的性质.

It’s the note of week3. (INT201 W3)

This is the note of INT201 Week2. The lecture is still focusing on decision, computation and language.

Alphabet A,
A* = {alll strings consisting symbols from A}
A subset L of A* is called a language
Question: For a language L, does exist an algorithm to check for any x, if x is in L?

This is the note of INT201(Decision Computation and Language).

The lecture of this week is mainly discussing about Preliminaries: principal mathematical ideas necessary to understand the material of the course.

根据预习的笔记修改了一些内容。

Decision, Computation and Language
This module is about the theory of computation and answering the question: “What are the fundamental capabilities and limitations of computers?”
这个模块是关于计算理论的，并回答这个问题:“计算机的基本能力和局限性是什么?”
The central theme: Are the languagues, their membership problems can not be solved (computed) Algorithmically.