Quote:
Originally Posted by oranges
I find your suggestion of taking 4A03 instead of 3A03 very intriguing. What topics from 3A03 do you think one should study rigourously before asking for a waiver for 4A03? Obviously taking 3A03 would be the best preparation for 4A03, but it would be nice to have a general idea of what I should be focusing on the most during my self-studying (especially if I were to go as far as replacing 3A03 with 4A03).
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First, it may be hard to actually
replace 3A with 4A (I was forced to take them concurrently for bureaucratic reasons, 3A is required to graduate, but I was also too lazy to argue my case with the registrar). But even taking them concurrently is a good idea; a lot of the ideas in 3A may seem theoretically unmotivated, and 4A provides the motivation.
Next year, first semester of 4th year math is really cluttered with courses (4A, 4X, 4B, 4E all in the same semester), so taking 4A early gives me much more flexibility in 4th year.
We covered ch. 1-11 and 16-20 of Carothers, with some omissions and some extras.
We started by reviewing metric space theory (i.e. metric topology stuff), and then from there generalized the results we got from 3A, which was all in 1 variable. In other words, we were simply talking about open n-balls instead of open intervals.
After this generalization, we had a bit of time to do some new stuff.
We covered Lebesgue theory, which is the model of integration that mathematicians today actually use, more-or-less; to be precise, they use a more general notion of
measure, Lebesgue measure being a particular case.
A last-ditch argument for 4A; it lets you look at mathematics differently. If you are interested enough to do mathematics on your own, outside of coursework, then consider this problem:
"Suppose (X, m) is a measure space and (M(x)) is a family of metric structures indexed by X. What does it mean for a sequence (i.e. function) over M(x) [i.e. an element of the product over X of the M(x)] to be integrable? What restrictions do we have to put on X, m, or on each M(x)?"
As you can see, this massively generalizes the notion of integration, you look at it in a different way -- and I don't think that I would be able to make sense of the question at all without 4A.