Week4

In this week, things get more complicated. I feel not quite comfortable translating Bi-implications into combinations of conjunctions and disjunctions. It is even more confusing to use manipulation rules; for example: (¬P∨Q)∧(¬Q∨P) = [(¬P∨Q)∧¬Q]∨[(¬P∨Q)∧P] = [(¬P∧¬Q)∨(Q∧¬Q)]∨[(¬P∧P)∨(Q∧P)], it is not quite easy to follow this method, though they are similar to mathematical calculating rules. But I believe as I practice more, I will be more familiar with these laws and will feel comfortable using them. Finally, I finished all the mathematical expressions and symbols and started to learn the proof in this week. The proof in this course is quite different to the prooves in math. The format of proof is interesting that I can prove from the 2 different side. It is more sufficient to prove from the 'conclusion'; and such method makes the proof more creative. During the lecture, the 'folding' problem was a little challenging for me and my group members. At first we folded 4 times， it was difficult to figure out the pattern; then we compared this pattern with folding 3 times, twice, and once, we can see that the crease of folding once is always in the middle. Similar to that, we found the left side and right side were somehow related to each other. After the professor's explanation, we finally figured out the pattern. Such activities were really fun and engaging, and I am looking forward to have more activities during lectures.