Week 2: Negation, conjunction, disjunction and tabulating truth

Hello Rod here,

Standard Negation
This week we explored negation more. I learned standard negation and I was surprised how negation changes a universal statement to a existential statement. Or if we are negating [P(x) => Q(x)] it can be equally expressed as a conjunction and as a single negation on Q: [P(x) ^ (negation)Q(x)].

Conjunction and Disjunction
I just learned these symbols this week. What helps me to remember them well is think of conjunction as the python syntax 'and' and think as disjunction as 'or.' This helps me in determining whether the entire expression would be true or not. So far this has been really helpful.

Tabulating Truth
Personally I was glad to have learned tabulating truth as a method to help better understand claims. I found the venn diagrams hard to read or visualize and when we started tabulating predicates it made a lot of sense and helped me identify the situations where the entire expression would be false or true.

This week what i has trouble with was the first set of questions on the tutorial #2 exercise. I found it difficult to translate the English claims into logical symbols at first. But at the start of the tutorial, soon as we took up two of them I was able to do all of them easily. I felt like I learned a lot from that tutorial and that as if I was learning a new language, as soon as I got the hang of understanding a few logical symbols and their placement to make the claim represent the english claim then the rest came very naturally for me.

This week was tough but I learned many things.

Week 1: Quantified Sets and Implication

Hello Rod here,

Universal and Existential Quantification
This week in CSC165 was fairly challenging for me. What I had difficulty this week with was understanding the difference between universal and existential quantification. Once I started looking over the examples from lecture and recognizing the keywords that define each claim such as: "all, every, some, exists) and the next step I would take is try to identify what evidence would cause each of these claims to be proven true or falsified. Applying this to the venn diagram was probably the biggest challenge for me. I had a very hard time visualizing whether the sets in the venn diagram would have to be occupied or empty in order to prove the statement false or true. At tutorial this was explained very well and we were quizzed on the exact same problem requiring us to draw a venn diagram showing what evidence will be needed in order to prove or falsify the statement given to us.

Implication
Also we began to look into implication which made sense to me. We looked at a statement in lecture and discussed how the implication has to be true if you are going to verify or falsify the statement. For example:
"If you have blue pants, then you have red hair"
To prove this false you would need to have evidence of someone who has blue pants(satisfies the antecedent) then does not have red hair. You cannot prove this false by saying that someone wearing green pants has purple hair.

Negation
From the last lecture I had a little difficulty understanding what negation does to the statement. How it affects the statement and whether it will still remain true or not. What I am going to do about this is ready over my notes, lecture notes and write out some problems.

Overall it was a good week I learned quite a lot.