Week 4

In  this week, we started to do some simple proofs. And the assignment 1 is due this week, assignment was not so hard, but I found some difficulties in veen diagrams. I know how to draw diagrams for two events, but I really can not understand for three or more events. 

In the lecture, proofs was not so hard, until now... We learned two ways of implications last week, according to truth table, so the whole technique of the proofs is translating one way to other way, and make them equal, or disprove it if they are different. for example,

 This is a typical proofs of this week, not so hard, we just need to show first statement is equivalent to second one, translating 'if P then Q ' to 'not P or Q', and we can prove it.

Anyway, I enjoyed to do proofs.