I Want You All To Know That An Arab Muslim From Tunis Proposed The Theory Of Evolution Near 600 Years

Nothing but respect for this mathematician's webpage

my love for topology is a very concave function with a very positive derivative

tietze theorem is fucking beautiful urysohn's lemma is pretty and separation axioms are cute

aand i animated some riemann integration today:

i could've chosen different partitions or a different function in order to achieve more frames but i like this anyway

I got a proof wrong on an exam. No points. 

Then, I thought about it for fifteen minutes outside of the exam, wrote it down, nailed it. 

I showed a classmate and told him what happened. He looked frustrated. He’d clearly had this happen before, too (haven’t we all?).  He said, “Don’t you hate it when that happens?”

I almost said yes. What the h*ck!? No. No, I do not hate it when I can fathom a deeply abstracted concept in mathematics. I never hate that. I the opposite of hate that. Expecting myself to immediately understand topics like this is unrealistic. I’m proud of being able to do it at all. Who cares if I did it in the exam or within the next hour? I DID IT. It’s mine now. I can do it whenever I want. Missing points on that problem doesn’t take the knowledge out of my brain. How dare I be taught that my knowledge is useless because I didn’t have it right at that moment. It’s just as good now. 

Education is not about the arbitrary numeric number ascribed to your ability to do things quickly in an arbitrary, restricted time interval. Education is about being able to do progressively more things, to understand progressively complex things. 

Tenacity and challenging yourself far beyond your limits is a hundred times more important than getting good grades. Because, when you’re one of .4 percent of the population who possess complete knowledge on a very complex topic, nobody cares how long it took you to do it, or how well you did it the first time you tried. 

Grades don’t discover new mathematics. Mathematicians do (even the ones who failed a basic topic in mathematics because their base way of thinking was too complex). Grades don’t advance medical research. Scientists do (even the ones who had to apply for their PhD programs 3 times in a row before they got accepted). Grades don’t make science fiction into real-world technologies. Engineers do (even the ones who dropped out of school because they wanted to build things, not talk about building things). 

Knowledge is power. Skills are power. Grades are constructs. Never trade actual understanding for a semblance of understanding. 

touch grassmannian

touching grass is not enough sometimes. sometimes what you actually need to touch is a math textbook

Zero to the power of anything is zero. Anything to the zeroth power is one. So what is zero to the zeroth power?

The world's most cited mathematicians would seem to be in disagreement about the issue

“Netflix and chill?”

No, PDF and cry

Every now and then I remember that Malbolge exists and I get to spend the better part of an hour cry-laughing at the world’s worst programming language

already starting off strong, but it gets worse

Wow! Sounds easy and intuitive to use! What’s the “crazy operation” you ask? We’ll get to that later. For now let’s see what a program in this language looks like :)

Thanks! I hate it!

it’s so difficult to work with that the first program was written by another brute force search program

mmmmm delicious base-3 arithmetic, what could go wrong? (For reference, that means this program forgoes the usual “0/1″ values of binary code in favor of a much more fun “0/1/2″ set of values)

ah.

Here’s how the language actually figures out what to do. It’s got 8 “simple” commands that can be executed easily by *checks notes* running the code itself through the modulo operation and taking the result.

As a bonus, on top of all that every single character in your code will now alter what every single other character does. So I hope you’re alright with cracking a cipher every time you add a new letter to your program!

oh god oh fuck.

behold, Malbolge’s primary arithmetic operation and what you’ll be using for most of your math while programming with it :)

This looks specifically designed to be the least logical math operation you could make, and knowing what the rest of Malbolge is I’d wager that’s precisely what happened. I never want to ever use this and it’s my favorite thing I’ve ever seen.

https://en.wikipedia.org/wiki/Malbolge

Anyways here’s the wiki page if you wanna read through it more deeply, I’m gonna sit here holding in my laughter staring at the hello world program again.

me : I love learning new things

Me when it’s time to learn anything new that I’m not instantly good at:

Me when I need to rotate 720 degrees to return to my original state

So the exponential function is given by

which evaluated at a real number x gives you the value eˣ, hence the name. There are various ways of extending the above definition, such as to complex numbers, or matrices, or really any structure in which you have multiplication, summation, and division by the values of the factorial function at whatever your standin for the natural numbers is.

For a set A we can do some of these quite naturally. The product of two sets is their Cartesian product, the sum of two sets is their disjoint union. Division and factorial get a little tricky, but in this case they happen to coexist naturally. Given a natural number n, a set that has n! elements may be given by Sym(n), the symmetric group on n points. This is the set of all permutations of {1,...,n}, i.e. invertible functions from {1,...,n} to itself. How do we divide Aⁿ, the set of all n-tuples of elements of A, by Sym(n) in a natural way?

Often when a division-like thing with sets is written like A/E, it is the case that E is an equivalence relation on A. The set of equivalence classes of A under E is then denoted A/E, and called the quotient set of A by E. Another common occurence is when G is a group that acts on A. In this case A/G denotes the set of orbits of elements of A under G. This is a special case of the earlier one, where the equivalence relation is given by 'having the same orbit'. It just so happens that the group Sym(n) acts on naturally on any Aⁿ.

An element of Aⁿ looks like (a[1],a[2],...,a[n]), and a permutation σ: {1,...,n} -> {1,...,n} acts on this tuple by mapping it onto (a[σ(1)],a[σ(2)],...,a[σ(n)]). That is, it changes the order of the entries according to σ. An orbit of such a tuple under the action of Sym(n) is therefore the set of all tuples that have the same elements with multiplicity. We can identify this with the multiset of those elements.

We find that Aⁿ/Sym(n) is the set of all multisubsets of A with exactly n elements with multiplicity. So,

is the set of all finite multisubsets of A. Interestingly, some of the identities that the exponential function satisfies in other contexts still hold. For example, exp ∅ is the set of all finite multisubsets of ∅, so it's {∅}. This is because ∅⁰ has an element, but ∅ⁿ does not for any n > 0. In other words, exp 0 = 1 for sets. Additionally, consider exp(A ⊕ B). Any finite multisubset of A ⊕ B can be uniquely identified with an ordered pair consisting of a multisubset of A and a multisubset of B. So, exp(A + B) = exp(A) ⨯ exp(B) holds as well.

For A = {∗} being any one point set, the set Aⁿ will always have one element: the n-tuple (∗,...,∗). Sym(n) acts trivially on this, so exp({∗}) = {∅} ⊕ {{∗}} ⊕ {{∗∗}} ⊕ {{∗∗∗}} ⊕ ... may be naturally identified with the set of natural numbers. This is the set equivalent of the real number e.