jts wrote:How many definitions are there in Elements, and how many of them contain technical terms that are left undefined?
There are probably no more than 200 definitions (it's been a while), but more than 100. I can't really answer the second question, but there are certain important things that are not defined explicitly but
implicitly by their assumed properties such as the notion of length.
speedchase wrote:and what percent of High schools teach using the elements, and what percent of high school students graduate understanding geometry?
The "it may still be" in my post strongly suggests that I don't know what they teach in high schools today. However, I begrudgingly teach some university classes from time to time, where it becomes apparent that many college students didn't graduate high school with an understanding of geometry. Perhaps they don't teach
Elements in high school anymore? I can't imagine that college students would have such poor understanding if they had studied
Elements.
For a couple of centuries, one could not be called an educated person without having studied
Elements, and the students of the first universities would definitely have been familiar with it.
Now, I am in no way suggesting that the quality of Jasiek's paper is comparable to that of
Elements, which is truly a masterpiece of masterpieces. However, from an analysis of the syntax, the arguments in
Elements are fairly low in complexity. Of course, part of the beauty of
Elements is that it uses elegantly simple arguments to prove some very nice things.
The domain of the logic being applied in Jasiek's paper is finite. This is pretty much as simple an environment as you can get in mathematics. It might have
a great number of simple things written in succession, which makes it look intimidating. Jasiek's word choices probably make things a bit worse, but he's not trying to sell the paper for money, so he might have put zero effort into making it more fluidly readable.
I actually think that Jasiek's
writing style would benefit a lot from additional mathematical training. Introducing just a sprinkle of symbolic notation in
the right places might make his definitions and arguments more concise and clear.
Also...
When I say that the complexity of Jasiek's ko paper is no more than that of
Elements, I am saying the arguments in both would look similarly complex if we removed the parts relevant to giving the arguments meaning and left only the parts necessary for making logical inferences. What is meant by this?
Consider the following paragraph: All swans are white. Any animal that can produce viable offspring by mating with a swan is also a swan. Ann the Swan at the local zoo is a swan. Bob the Bird at the local zoo mated with Ann the Swan and produced viable offspring. Therefore Bob the Bird is a swan and is white.
Now try to ignore the meaning of those sentences and look at isolate the parts that are relevant to the argumentation by replacing some terms (here's one crude approximation): Any object x that has property S also has property W. For any objects x and y, if object y has property S and the pair (x,y) taken together has property PVO, then x has property S. Specific object A has property S. The pair (A,B) taken together has property PVO, where B is a specific object. Therefore B has properties S and W.
These statements have no discernible meaning, but their logical structure and correctness are the same as those in the plain English version from which they were constructed.
A small but not insignificant part of the reason that
Elements is easier to read than Jasiek's ko paper is that most people already have some familiarity with and intuition about the many objects and properties (line, point, angle, circle, parallel, etc.) that are defined in the former (in the same way we are familiar with swans, mating, offspring and white) whereas we have very little familiarity with the objects and properties being described in the latter. This is nothing that cannot be overcome with some patience and time.
Lastly...
I'm not saying that Jasiek's paper is correct. I'd have read it carefully to say that (and like most people, ko rule theory isn't something that interests me). However, if we're just talking about it's complexity, then I only need to scan its syntactical structure, which can be done fairly quickly.
Now...
I believe y'all were discussing something far more interesting than this ko paper.
PS: The bit-width thing was ridiculous... Some people started posting moves by their coordinates in their Malkovitch games (instead of entire diagrams), presumably to save bits. This shows that people trust the admins quite a bit. That trust might have been slightly compromised.