# Functional Analysis vs. Complex Analysis?

1. Dec 7, 2014

### Feynman's fan

I have one slot to fill in in the coming term. The two candidates are Functional Analysis and Complex Analysis (both on the undergraduate level). Here are some questions:

1) Which one would you pick and why?

2) What other classes in the standard B.Sc. math curriculum rely on either of these two? (E.g. Advanced Probability Theory uses many results from Functional Analysis).

3) Which one is harder in your opinion? (The question is obviously subjective but I think most people would agree that, say, Real Analysis is harder than Linear Algebra, even if they have the same amount of credits and the same prerequisites.)

Any remarks are hugely appreciated.

2. Dec 7, 2014

### dextercioby

If you're pursuing a degree in Maths, then both are a must of the curricula. If you had real analysis, then complex analysis comes logically next.

3. Dec 7, 2014

### Feynman's fan

I'm going to take both eventually but I have only one free slot left in my bachelors program. How would you compare the difficulty level (assuming that Complex analysis is fully rigorous as well).

4. Dec 7, 2014

### dextercioby

Functional analysis is conceptually more difficult (starts off with point set topology) and has both real and complex analysis as prerequisites.

5. Dec 8, 2014

### homeomorphic

I'd go with complex first.

Functional analysis is a subject that takes tons of prerequisites to be well-motivated and be done properly, although you can try to get by with less. I'd suggest doing a lot of PDE and maybe read a little about integral equations, Fourier series, and Sturm-Louiville theory, first, but maybe that's just me and my stance against too much unmotivated abstraction. You can also try to learn these subjects alongside functional analysis, and sometimes it will give you a more elegant way to think about things. Measure theory is also good to have.

As far as hardness goes, once you get to a certain point, it's often the professor or the textbook that determine hardness more than the subject does.

6. Dec 8, 2014

### HallsofIvy

Complex analysis. Functional analysis will be much harder anyway but it will help to have taken complex analysis before you take functional analysis.