2014-01-25 20:42:42 +00:00
|
|
|
---
|
|
|
|
format: markdown
|
|
|
|
toc: yes
|
|
|
|
title: Mathematical Proof Study Notes
|
|
|
|
...
|
|
|
|
|
|
|
|
# Texts
|
|
|
|
|
|
|
|
- *Book of Proof*, Richard Hammack
|
|
|
|
|
|
|
|
# Reading Notes
|
|
|
|
|
|
|
|
## *Hammack*, 25 Jan 2014
|
|
|
|
|
2014-01-25 20:45:13 +00:00
|
|
|
All of Mathematics can be described with *sets*.
|
2014-01-25 20:42:42 +00:00
|
|
|
|
|
|
|
*set*
|
|
|
|
: A collection of things. The things in the set are called *elements*.
|
|
|
|
|
2014-01-25 20:45:13 +00:00
|
|
|
An example of a set: $\{2,4,6,8\}$
|
2014-01-25 20:42:42 +00:00
|
|
|
|
|
|
|
The set of all integers:
|
2014-01-25 20:45:13 +00:00
|
|
|
$$ \{\dots, -4, -3, -2, -1, 0, 1, 2, 3, 4, \dots\} $$
|
2014-01-25 20:42:42 +00:00
|
|
|
|
|
|
|
The dots mean the expressed pattern continues.
|
|
|
|
|
|
|
|
Sets of infinitely many members are *infinite*, otherwise they are
|
|
|
|
*finite*.
|
|
|
|
|
|
|
|
Sets are *equal* if they have exactly the same elements.
|
|
|
|
|
2014-01-25 20:45:13 +00:00
|
|
|
E.g. $\{2,4,5,8\} = \{4,2,8,6\}$ but $\{2,4,6,8\} \neq \{2,4,6,7\}$.
|
2014-01-25 20:42:42 +00:00
|
|
|
|
2014-01-25 20:45:13 +00:00
|
|
|
Uppercase letters often denote sets, e.g. $A = \{1,2,3,4\}$.
|
2014-01-25 20:42:42 +00:00
|
|
|
|
|
|
|
To express membership, we use $\in$, as in $2 \in A$.
|