CSC165H1 week4

We finished CSC165 term test1 this week. The questions are not very hard since they seem to be similar to the past exams. But I found that the exam time is not very sufficient for me and I almost don't have time to check my answers.So I think I should practice more from now to be skilled.

Besides, we learned more about proof this week.But in the tutorial, we are told that we don't need to know and to write down every step of proving. So this week's concept focus more on the standard format of proofs.But I am wondering whether we will learn how to prove these questions.Many questions of them are like math problems and require math knowledge, and I hope I won't unable to prove many questions only because of my poor math.....

BTW,
Happy thanksgiving!

CSC165H1 WEEK3

This week we learned something about Bi-implications,transitivity mixed quantifiers and some proofs. As the condition of statements become more complex, it is difficult sometimes to write the statement symbolically and negate it.

Also,we did assignment 1 this week. Though it seems simple, I found some questions through the process of finishing it. The first is how to understand the word "unless" in sentences. I still remember "unless"' is equal to "if not" according to Professor Danny Heap. However, my partner views that the statement “all acronyms are  catheterized unless they are  bifurcated " implies that  an acronym is either catheterized or  bifurcated but cannot be both, while I argue that an acronym can be both catheterized and bifurcated. And  we cannot persuade each other. So we decided to ask the professor next week and hope we can get a result. 

Another problem is that I found it's hard for me to choose "⇒" or "^" when change a sentence into symbolic form. For example, "There exists an A that is B", should it be "A⇒B" or "A^B"? Ok, another question awaits to ask! ==

CSC165 week2

I had to change my section from L0101 to L5101 this week because I have one-hour conflict.I chose the section taught by  Danny Heap at first since I have taken his csc104 and I really like the teaching style of him. Fortunately, I found Professor Zhang is also great, explaining knowledge very clearly and logically.

This week's topic is a little bit hard to acquire for me, especially the truth tables.Like the table below(from Professor Zhang's slides), I am confused why when P is false and Q is true then P can imply Q. After discussing it with my classmate, we think it may because if q is false(without other predicates), then nothing can imply q. Otherwise, since q is correct objectively, every predicate is able to imply it( even if the predicate is false).

Also, I think practice is really important. There are so many rules in this chapter, and I found it is so difficult to memorize them mechanically. Like the professor Zhang said, to memorize them completely, we should understand them first and practice a lot.       

             

CSC165 Week1

I chose CSC165H1 since I plan to minor in computer science. To be honest, I didn't know much about computer science before. But I took CSC104H and CSC108H last academic year, and found that computer science is challenging but interesting, especially the process to complete the project. And unlike tradinational CS courses, I found CSC165 tends to focus on the thinking of logic rather than the way of programming. And the thinking of logic also benefits to the programming to a large degree.

We learned some quantification from last week, and we met a lot of questions which require us to judge whether a cliam is ture.I think the core to deal with these questions is tring to find a counter-example. More exactly, we just need to find one counter-exmaple rather than all of them to prove the claim is wrong. In contract, we need to verify that all samples(or examples) satisfy the claim  in order to prove the cliam is true. And we can also ensure there is no counter-example at all.

And we also learned expressing implication this week. To transfer natural language into universal quantification requires us to understand the sentence  clearly. However, since I am not a native speaker, sometimes it is a little confusing for me to understand the sentence exactly especially when some  prepositions exist. For exmaple, "Don't knock it unless you've tried it".The  professor said "unless" means "if not", which makes me more confused. However, I founn a way to deal with it. I translated it into Chinese , and aftering understanding it completely, I can find the logic relation of the sentence.