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Comment Re:Exam, not a job (Score 4, Insightful) 177

Broadly speaking, yes, the point of an exam is to test the examinee's knowledge. However, that is a very vague and imprecise statement. In principle each exam item is meant to assess a specific piece of knowledge. For example, the example of finding leap years is likely intended to get students to demonstrate an ability to iterate using a for loop with a nested conditional. One could simply tell the examinee that this is the intention, but then you are essentially telling them how to answer the question, which reduces the validity of the assessment (to what extent is, of course, a matter of debate). At the end of the day, the exam writer needs to know if an examinee can actually recognize a situation which calls for iteration, and whether or not they actually code up a valid for loop.

On the other hand, if a student comes up with a valid though unexpected solution, the fault is with the writers of the exam item, and not the examinee. The correct course of action in such a case is probably to give the examinee credit for their correct answer, or to remove the exam item from the computation of scores for all examinees. Hopefully, the knowledge which the invalid exam item was meant to assess is tested elsewhere—one or two problematic exam items should not seriously threaten the overall validity of an exam which is made up of many questions.

Comment Re: Seems quite a lot larger... (Score 1) 222

No... if I wanted to solve that DE, I would integrate both sides with respect to $x$. On the right, the integral is easy enough to compute. On the left, it comes down to an application of the fundamental theorem of calculus. The Leibniz notation is convenient in this case, since it lets you treat the differential as a number, but the usual exposition relies on actual theorems which justify this kind of manipulation. It should also be noted that Abraham Robinson went over this in the 60s...

Comment Re:People, Just Floss (Score 1) 208

You don't generally realize how odd the whole situation is until you need dental surgery, and get deep into the confusion of what's covered by dental vs medical insurance.

So true. My wife is having surgery next month to remove a very belated wisdom tooth, and finding an oral surgeon that could bill it to our medical insurance was ridiculous. Ended up having to go with somewhere an hour away, even though there's a surgeon 10 minutes from our house.

Comment Re:actually (Score 1) 105

Shinichi Mochizuki has a solid history of producing good mathematics. While it is possible that he is trying to pull a fast one, that seems quite unlikely, given his reputation. The most charitable explanation is that he has invented a new branch of mathematics (the "inter-universal Teichmüller theory") in order to resolve the ABC Conjecture, and that the "newness" of this approach is causing difficulty for outsiders.

Comment Re:actually (Score 1) 105

This is not at all true. First off, mathematics itself has many different highly specialized sub-fields, many of which don't communicate effectively between each other. An complex analyst and a homotopy theorist speak very different mathematical languages, and may have difficulty communicating their ideas to each other. It is reasonable to suggest that this represents a different "cultural" background (as per Tylor's definition, these differences are differences in knowledge and belief, as well as differences in language).

Additionally, mathematicians from different parts of the world conduct mathematics differently. The internet and the wide-spread adoption of English as the de facto language of discourse has ameliorated this problem some in recent history, but there are still very significant cultural differences between American, European, Russian, and Japanese mathematics (for example). The approach that one takes in tackling a mathematical problem does depend quite a bit on where one learns it. As a historic example, Ramanujan was interesting to Hardy not just because he was producing interesting results, but because he was producing these results in an idiosyncratic way which differed immensely from the British approach.

Hence the original question

is it obtuse because he's trying to pull a fast one, or does it appear obtuse because he's form a different cultural background than?

is entirely reasonable.

Comment Re:Pure stupidity (Score 1) 457

My bachelor's degree, from the University of Nevada Reno is a Mathematics BA (Statistics emphasis). The difference between that degree and a Mathematics BS (Statistics emphasis) is that the BA requires a foreign language, does not require any CS, and is not required to take numerical modeling (which is essentially a CS class). Otherwise, the requirements for the two degrees are identical. The same structure exists for the other possible emphases in mathematics: the BA requires a foreign language and does not require any CS.

Comment Re:This is ridiculous (Score 1) 274

These days? Better get in line - there's so much stuff that deserves massive public outcry, I doubt this even makes the top 10.

Some news stories, a smattering of angry people say they'll cancel their subscriptions, life goes on and Amazon gets more money.

It sucks, but personally it's still worth it to my household, another $20/year is way below my threshold for going on the warpath.

Comment Re:Mandelbrot beat them (Score 1) 189

I'm not disputing anything that Mandelbrot said. He himself walked back from a formal definition of a fractal, and ultimately chose not to give a precise mathematical definition. From the second edition of Mandelbrot's book (on page 459):

...to leave the term "fractal" without a pedantic definition, to use "fractal dimension" as a generic term applicable to all the variants in Chapter 39, and to use in each specific case whichever definition is the most appropriate.

In the first edition of the book, Mandelbrot suggested that a fractal should be any set with Hausdorff dimension strictly larger than its topological dimension (note that this does not mean that the Hausdorff dimension is non-integer; only that it is larger than its topological dimension). However, it was pointed out that there are lots of sets that we intuit as fractals, but which fail to satisfy this property (the Devil's staircase, for example, has both topological and Hausdorff dimension equal to 1 (it is a rectifiable curve)).

Falconer, who (in my opinion) is a much better source for a rigorous mathematical discussion of fractals, also chooses not to give a formal definition. From the introduction Fractal geometry. Mathematical foundations and applications (pp. xx--xxi):

In his original essay, Mandelbrot defined a fractal to be a set with Hausdorff dimension strictly greater than its topological dimension... This definition proved to be unsatisfactory in that it excluded a number of sets that clearly ought to be regarded as fractals. Various other definitions have been proposed, by they all seem to have this same drawback.

My personal feeling is that the definition of 'fractal' should be regarded in the same way as the biologist regards the definition of 'life'. There is no hard and fast definition, but just a list of properties characteristic of a living thing...

When we refer to a set F as a fractal, therefore, we will typically have the following in mind.

  1. F has a fine structure, i.e. detail on arbitrarily small scales.
  2. F is too irregular to be described in traditional geometric language, both locally and globally.
  3. Often F has some form of self-similarity, perhaps approximate or statistical.
  4. Usually, the 'fractal dimension' of F (defined in some way) is greater than its topological dimension.
  5. In most cases of interest F is defined in a very simple way, perhaps recursively.

Comment Re:Abandoned games... (Score 0) 308

They don't offer it because basically *nobody* (i'm sure you'll find a few exceptions here to try and prove me wrong) running a game of any real size offers it. That's not how MMO's work

They're not going to run separate servers for every patch level, just to accommodate folks that forgot they signed up for a game that was going to be constantly updated.

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