# When did you first encounter proof based mathematics?

1. Nov 7, 2012

### Best Pokemon

When did you first encounter "proof based" mathematics?

I've been reading a few forums and have seen many posters say "methods based" mathematics like calculus is easy. The posters would then state that "proof based" mathematics is so hard and calculus isn't high level.

So when did you first encounter "proof based" mathematics in a classroom setting? Was it in high school or university/college? What year in high school or university did you encounter it?

Edit: What grade did first encounter it (if it was in high school)?

2. Nov 7, 2012

### micromass

Re: When did you first encounter "proof based" mathematics?

My first encounter with proofs was probably in high school (freshman-sophomore year). The proofs were very easy though, but I didn't quite grasp them. Throughout highschool, the teachers kept emphasizing proofs and I got better at them. But I wouldn't say that the classes in high school were proof-based: the proofs were usually very easy and there weren't a lot).

My first real proof based course was an analysis course in freshman year. The course was literally filled with proofs. I didn't find the course very hard, since I was acquainted with proofs in high school.

So all in all, I had a very gradual transition into proof-based mathematics. I think that is actually the best way to introduce proofs.

3. Nov 7, 2012

### symbolipoint

Re: When did you first encounter "proof based" mathematics?

Geometry in high school. Mostly proof-based, very difficult.

4. Nov 7, 2012

### Klungo

Re: When did you first encounter "proof based" mathematics?

I'm taking my first real proof based course (linear algebra) and a half-proof based course (complex variables) as a freshman at uni. I understand the proofs and can write any reasonable proof with little trouble (some proofs can take 30min-1hr) but the result is rewarding(either course). Complex variables are partially filled with proofs but not necessary rigorous in the sense that what we assume is already true (even if it may not have already been proven) and often skipping steps.

Regardless, both courses are fascinating. The thing that fascinates me the most is seeing a collection of axioms slowly build an entire branch of mathematics.

US highschools do a very poor job at introducing proofs. And I mean zero proofs in anything but geometry. I learned about proofs outside of class about 1-2 years ago (Junior/Senior).

5. Nov 7, 2012

### homeomorphic

Re: When did you first encounter "proof based" mathematics?

Usually, you encounter proofs for the first time in high school geometry. If you take calculus, you might see a few proofs. In linear algebra, maybe a little bit more. Then, you might take some kind of transitional class--I took a set theory class, for example. Then, I took real analysis, which was my first really serious proof-based course.

6. Nov 7, 2012

### alissca123

Re: When did you first encounter "proof based" mathematics?

I took my first proof based course as a freshman. At my university, if you study math, physics, computer science or actuarial science, with very few exceptions, all the math courses you'll take are going to be proof based.

7. Nov 7, 2012

### phinds

Re: When did you first encounter "proof based" mathematics?

I think in the US at least everyone's first encounter with proof-based math is high school geometry. I remember well the delight I felt at finding that math wasn't just about algebraic equations and arithmetic. I loved doing the proofs.

8. Nov 7, 2012

### MarneMath

Re: When did you first encounter "proof based" mathematics?

Geometry in high school, but it didn't really click for me that this was a 'proof-based' course. At university, calc I with spivak was my first real proof based course. I was an immature student and basically flunked hard, but lesson learned!

9. Nov 8, 2012

### chill_factor

Re: When did you first encounter "proof based" mathematics?

i believe that is atypical. at my school only math and CS majors took proof based math. in physics you never touched proofs because math proofs are useless in physics. just a hint: there are indeed functions in Hilbert space that do not vanish at infinity. Are they valid wavefunctions? no of course not they're completely unphysical. But the math works... no here is when you ignore the math and say that simply can't exist.

First time I ever saw an epsilon sign that wasn't a physical constant was 3 months ago when I started grad level mathematical physics. Hit me like a reinforced concrete wall.

In other schools they don't teach it like this, but my current professor loves theoretical math, since that was the way he was taught... so...

10. Nov 8, 2012

### micromass

Re: When did you first encounter "proof based" mathematics?

What is a function in Hilbet space? And what does it mean that it vanishes at infinity???

11. Nov 8, 2012

### chill_factor

Re: When did you first encounter "proof based" mathematics?

sorry. Wavefunctions which are vectors in Hilbert space.

However, vectors in Hilbert space need only be square integratable, and not necessarily have zero value at infinity such that psi(x), when lim(x->infinity) psi(x) =/= 0. Physically, we restrict attention to wavefunctions such that lim(x->infinity) psi(x) = 0. Straight off Griffith "Quantum Mechanics" pg. 14 footnote 12.

Well that wasn't a good example of the uselessness of proofs to start off with...

12. Nov 8, 2012

### micromass

Re: When did you first encounter "proof based" mathematics?

Oh, you're talking about $L^2(\mathbb{R})$ or something? Yeah, then it makes sense. But there are more Hilbert spaces than that

13. Nov 8, 2012

### chill_factor

Re: When did you first encounter "proof based" mathematics?

yeah that was quite embarrassing to talk about the uselessness of proofs and make that mistake =)

guess I may have to re-evaluate my position about their usefulness but their difficulty is not affected.

14. Nov 8, 2012

### Darth Frodo

Re: When did you first encounter "proof based" mathematics?

Hmm, first encounter with proofs was middle school geometry, but my first encounter with a proof based class is Linear Algebra 1 that i'm taking at the minute.

It's actually great. It's my first real encounter with mathematics. The lectures are extremely heavy on proofs. Only 1 or 2 corollarys are left as "given" EVERYTHING else is proven and it's great I love it. But the exams are 100% computation so there pretty easy LOL.

I kinda see it as the best of both worlds.. :)

15. Nov 8, 2012

### espen180

Re: When did you first encounter "proof based" mathematics?

My first proofs were induction proofs during my first year in high school, then direct, contrapositive and ad absurdum proofs came during second year. Looking back, there were quite a few proofs in my high school textbooks, although they were not explicitly announced as proofs. My university classes were all definition-theorem-proof from the get-go.

16. Nov 8, 2012

### Devils

Re: When did you first encounter "proof based" mathematics?

There are various types of proofs in proof theory http://en.wikipedia.org/wiki/Proof_theory#Kinds_of_proof_calculi

There is a theorem prover using set theory http://en.wikipedia.org/wiki/Zermelo–Fraenkel_set_theory called Metamath. They prove a wide variety of theorems just using set theory.
eg proof of triangle inequality http://us.metamath.org/mpegif/abstrii.html

You can even use proofs to construct programing languages. Prolog is based on a type of Horn-clause logic and running a Prolog program is equivalent to generating a proof
http://en.wikipedia.org/wiki/Prolog

17. Nov 8, 2012

### FalseVaccum89

Spivak for calc I? Wow.

To the OP: The way proofs are presented in most US high school courses (if presented at all) makes them seem just as banal as straight algebraic manipulation. At least in my experience. . .

18. Nov 8, 2012

### Lavabug

Re: When did you first encounter "proof based" mathematics?

I remember proofs as far back as geometry and precalculus/trig before university, I don't know remember when exactly, but I'm pretty sure I had precalc/trig in 9th or 10th grade, since I had calculus in 11th (not a US student).

My university encounters with calculus (also Spivak/Apostol and later Marsden) and linear algebra in my first year of university also did not skimp on the proofs. I don't remember proofs in high school calculus.

19. Nov 8, 2012

### WannabeNewton

Re: When did you first encounter "proof based" mathematics?

This is quite normal if one takes an honors calculus sequence. The usual suspects are either Spivak or Apostol if the course is any good.

20. Nov 8, 2012

### thephystudent

Re: When did you first encounter "proof based" mathematics?

I also learned my first proofs in high school, first geometrical like proving that two triangles were congruent, but i think my first "serious" proof was that sqrt(2) is irrational.

I agree that many theoretical math proofs are rather useless for physics and you simply don't have the time to learn the same background for all the math you use as a mathematics student does. But i believe one of the basic things about becoming a physicist and a scientist in general is being critical and question everything. And it's definately useful to know were basic math as l'hôpital's rule or the chain rule come from, knowing why this stuff works so why you can appy it.