998244353
Joined 4 years ago
Joined 4 years ago
The purpose of high school is to give you a wide foundation on everything.
The purpose of an undergraduate degree (in math) is to give you a wide foundation (in math).
In a (math) PhD, you are generally hyper-specialized in a very, very narrow area (of math).
This doesn't "need to" exist, it's just a funny parody that someone made.
You can represent any function f: [-pi, pi] -> R as an infinite sum
f(x) = sum_(k = 0 to infinity) (a_k sin(kx) + b_k cos(kx))
for some coefficients a_k and b_k as long as f is sufficiently nice (I don't remember the exact condition, sorry).This is very useful, but the functions sin(x), sin(2x), ... , cos(x), cos(2x), ... don't constitute a basis in the formal sense I mentioned above as you need an infinite sum to represent most functions. It is still often called a basis though.
This vector space also has a basis (even if it is not as useful): there is a (uncountably infinite) subset of real->real functions such that every function can be expressed as a linear combination of a finite number of these basis functions, in exactly one way.
There isn't a clean way to write down this basis, though, as you need to use Zorn's lemma or equivalent to construct it.
Applying general design principles without taking actual use cases into account is the worst.
A common one is putting heaps of whitespace around each cells in a table. Visually appealing, sure. But unusable if I need to look at more than 8 rows at the same time.
But what they're getting at is that we also want to gain an insight of "what is really going on", and it will take time to distill this proof into a theory that gives us a more complete understanding.