This is how my weekdays have been looking lately. And, surprisingly, I can't say that I've hated it thus far. It's actually been pretty enjoyable. I've been doing really well on my homework assignments. I've been able to keep up with everything yet still manage to free up my weekends enough to enjoy my time here in Budapest. It's weird how much different things are here versus at Lawrence. For example, by this time at Lawrence, I would be prepping for some of my midterms. Here, I don't think that I have a midterm for another two-three weeks. It's really been throwing me off, but in a good way. I'm so prepared for all hell to be breaking loose in terms of workload any day now, but that has yet to happen... and I'm gonna take advantage of this free time while I can.
The grading systems here are so different. For many of my classes an A is an 80% or higher. For other's it's 85% or higher. I have no classes with the american grading scale of 90%. So, for some of my classes, it is completely possible for me to not take the final exam at all and still fairly easily pass the class. In comparison to Lawrence, this is heaven. At Lawrence, getting an A in any class is a major accomplishment. A's just don't happen, unless you're crazy dedicated to school and have no social life or, like some of my friends, are dependent on drugs like Adderall. Here, for probably the first time since graduating from high school, getting straight A's is actually a possibility. Now, I don't know how much I'm jumping the gun by saving all this, and I sure hope that I'm not jinxing myself, but so far, things seem to all be going pretty smoothly.
Now, since one of the main reasons I'm writing this blog is part of my service project for the Gilman scholarship, I am expected to post a problem every week (or so) and work it out for you all. I know that some of this math may be a little bit above most of my readers, so I will try to break it down as best as I can. Since last time I did a problem from my MPS (mathematical problem solving) class, I would like to post one today from my set theory class. The problem is as follows:
Prove that the set of English sentences is countable.
Recap: Sets are groups of elements. Sets are defined by their elements, so for example a set could be something like {1,2,3,4,5}, {dog, cat, fish, bird, flower}, the set of the real numbers (all numbers that are not imaginary, so 5/6, .45379523, 1, 0, -.4238972, infinity, etc), etc. These sets are not required to hold any rules besides the ones described. So I could say "Let S={x element of N: x>0}" and that would translate as let S be the set of all natural numbers x, such that x is greater than (not equal to) 0".
Definition: Countable sets are sets that can be enumerated. Or in other words, there must exist some function that will map the set to the natural numbers (1,2,3,4,...). So the rational numbers are countable, but the reals are not. (I'll not get into more on this).
Proof: (here is my exact answer with my commentaries to you all written in bold) Notice: All English sentences= the union of all n letter word long sentences (with n ranging the natural numbers [since you cannot have words or zero or negative length]). N word long sentences are countable by the following logic: 1 word long sentences are countable because each letter has only 26 options (less if you consider proper grammar) and every proper word is finite. Thus if you order the sentences alphabetically, you'll see that the set of one word sentences is countable. By the same logic, if you continue to order sentences alphabetically throughout each word, you'll find that 2 word, 3 word, ... n word long sentences are countable.
You can then order the sentences in the following manner: 1 word (alphabetically), 2 word (alphabetically), ... n word (alphabetically). With proper grammar, sentences usually have a finite number of words.
Thus we note that the union of countable sets is countable (even when n is infinite) (we're unioning [taking all elements of said sets and adding them to a new set, deleting extra repeats] the sets of sentences of different word lengths [which are countable] a finite number of times. Thus, we'll get a countable set [just order the sets based on their word number per sentence, and alphabetize them. you know have an enumeration]) and therefore the set of all English sentences is countable.
This was a fun problem, but also a fairly basic question. It is very hard for me to break down more complex questions for you all without having to do an extreme amount of background explanation. I will put up another more cultural post (probably on my recent excursion to the chocolate/ sweets festival or on my experiences cooking here).