(CSC165)_Oct 17_Proof

During the past two weeks, in addition to mid-term and assignment, we begin to learn writing proofs using the logic related knowledge we had. It was first actually very impressive that the professor mentioned that he focus more on the structure of the proof rather than the specific technique used in the the proof. It actually make a lot sense since CSC165 is more about logical thinking rather math, and it is particularly important because we can apply the knowledge we potential will learn in the future to it.

Basically, for a direct proof,  the structure is generally:

Assume quantifier (domain) ....

    Assume .....

        Let ___ be ___

        Then .....

        .

        .

        .

        Then ....

    Then ....

Then....

(Note: the indentation is also a important part of the structure.)

In addition to a direct proof, we have choices proof the contrapositive, and disproof the negation.