Friday, 31 October 2014

Taming of the Proof - Week 8

While the topic of the course has switched to theory of computation, and more specifically algorithm analysis, I have been more focused on the regular math proofs we have been doing. This is largely due to the assignment that is due on Monday and the midterm that is on Tuesday. While it is surprising that my ability to solve proofs is getting better very quickly, I am noticing some common trends in where I am stuck with solving proofs. I seem to be able to find a conclusion and then show how I came to that conclusion but I struggle with identifying the entry point of where to start in that proof. This is especially true when trying to prove a statement with a format such as p Ù q. You cannot assume p and so where do you begin in your proof to prove p? There must be some base assumption of p that is legitimate to start with. My problem seems to be identifying what is the correct base assumption. I have had to rewrite numerous proofs as I realized I was starting with the consequent and deriving the antecedent.

One of the most useful (but perhaps obvious) lessons I have learned this week related to base assumptions is that proofs cannot start with a tautology. When trying to show that two different things are equal, I tried to show how you can start with p = p, which could be derived to show that p = q.  However, as the proof started with a tautology it is invalid. I had to go back and find an attribute of p that would later link it to q. In the end it was successful but it was not the most intuitive step to take.


Overall, while I am getting better at writing proofs, the ordering of steps and the entry point of a proof is still something I need to work on. Hopefully with some more practice, it will become more natural. 

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