I will take notes in English for this course. :P

Propositions & Connectives

Propositions

Which is simply a statement which is either true or false.
These statements are all propositions:

1. 1+1 = 2. ( T )
2. TYUT is the best university in China. ( F )

These statements are not propositions:

1. 8+7
2. 2x+3x^2=9. ( What is x? )

And these statements aren't propositions either: (although some books say they are)

1. Panda often eats bamboo. (Often)
2. Haolong Xu is popular. (what is popular?)

Connectives

Propositions can be joined together to describe more complex statements with connectives like 'and' , 'or' and 'not'.

The most important and subtle propositional form is an implication.

It's truth tables:

law of the excluded middle

It's a basical principal that , for any proposition P, either P is true or ¬P is true (but not both). Thus P ∨¬P is always true.