Friday 26 September 2014

Csc 165 week 3: Conjunction, disjunction, negation, implication

One of the more interesting things we went through this week in lecture was negation. As a general rule of thumb existential can be negated to universal and vice versa. A implies B is negated to A and not B. Thinking about negation in human language helps with the visualisation and understanding of the concept. The concept sounds like it will be easier to understand after more practice.

Truth tables on the other hand is a relatively harder concept for me to understand.it is a little hard to follow when we say P implies (Q implies R). does it mean that when P is true it implies that Q implies R is true which would mean that Q needs to be true to imply R is true. it took a while but eventually i realised that looking at it backwards is easier. In the sense that if R is true and Q is true statement Q implies R is true thus if P is true whole statement will thus be true.

In tutorial one person brought up the point that the statement 'only if''is technically the same as the statement 'if and only if' in the sense that lets say if we say a person resigns only if he is exposed to the media. Then at lest from the the point of human language exposing him to the media would imply he resigns and since he only resigns if he is exposed to the media the reverse is also true. however I would argue that this is due to the nuances in the human language which contributes to the misunderstanding. we can also say that there will be a rainbow only if it rains. Here a rainbow would imply it rained but the reverse in this case is not true since raining will not guarantee a rainbow. thus I think it would be better to not rely too much on the human language in cases like this and assume only if is an implication in one way.The debate on this subject made the tutorial a lot more interesting then it was last week. hopefully we'll have another spirited debate in tutorial again next week.

Friday 19 September 2014

Csc165 week 1 ~ 2 :precision, quantifiers, verify/falsify, sentences, symbols

During the 3 hour lecture of the 1st week the professor introduced the concept of ambiguity and precision in language. It was interesting to note that in mathematics and computer science where precision should reign supreme, at least for the programmer themselves ambiguity which also refers to intuition plays a large part in understanding a concept.The concept of precision in computer science while not particularly hard required several readings to clearly understand especially parts where he 'translates' computer code to human language.

The concept of quantifiers like universal and existential quantifiers were pretty intuitive and having taken Mat137 I did not have much problems with any of the second week's material. The concept of sets is intuitive if visualised as a venn diagram. however the concept of implication gave me abit of trouble. its a little confusing for statements such as 'Login is required to view content' where content viewed implies login.it took awhile but after a little reviewing it became less confusing.

overall week 1 and 2's course material was relatively simple. However from what I heard its going to get alot harder from here on out. Hopefully i can review before each lecture and go prepared.