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1500 questions
57
votes
3 answers
How to think of the group ring as a Hopf algebra?
Given a finite group $G$ and a field $K$, one can form the group ring $K[G]$ as the free vector space on $G$ with the obvious multiplication. This is very useful when studying the representation theory of $G$ over $K$, as for instance if…
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Will
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57
votes
3 answers
Probability that a quadratic equation has real roots
Problem
The premise is almost the same as in this question. I'll restate for convenience.
Let $A$, $B$, $C$ be independent random variables uniformly distributed between $(-1,+1)$. What is the probability that the polynomial $Ax^2+Bx+C$ has real…
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Hungry Blue Dev
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57
votes
6 answers
Does $\zeta(3)$ have a connection with $\pi$?
The problem
Can be $\zeta(3)$ written as $\alpha\pi^\beta$, where ($\alpha,\beta \in \mathbb{C}$), $\beta \ne 0$ and $\alpha$ doesn't depend of $\pi$ (like $\sqrt2$, for example)?
Details
Several $\zeta$ values are connected with $\pi$,…
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GarouDan
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57
votes
2 answers
Why doesn't Cantor's diagonal argument also apply to natural numbers?
In my understanding of Cantor's diagonal argument, we start by representing each of a set of real numbers as an infinite bit string.
My question is: why can't we begin by representing each natural number as an infinite bit string? So that 0 =…
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usul
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57
votes
2 answers
Order of general- and special linear groups over finite fields.
Let $\mathbb{F}_3$ be the field with three elements. Let $n\geq 1$. How many elements do the following groups have?
$\text{GL}_n(\mathbb{F}_3)$
$\text{SL}_n(\mathbb{F}_3)$
Here GL is the general linear group, the group of invertible n×n matrices,…
user9656
57
votes
14 answers
Is there a math expression equivalent to the conditional ternary operator?
Is there a math equivalent of the ternary conditional operator as used in programming?
a = b + (c > 0 ? 1 : 2)
The above means that if $c$ is greater than $0$ then $a = b + 1$, otherwise $a = b + 2$.
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dataphile
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57
votes
1 answer
How does TREE(3) grow to get so big? (Laymen explanation)
I am not a mathematician but I am interested in big numbers. I find them to be really interesting, almost god-like.
I am watching a series of videos from David Metzler on YouTube. I have a basic understanding of some fast growing functions.
David…
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Josh Kerr
- 747
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57
votes
10 answers
A really complicated calculus book
I've been studying math as a hobby, just for fun for years, and I had my goal to understand nearly every good undergraduate textbook and I think, I finally reached it. So now I need an another goal. I've just found a very nice book /S. Ramanan –…
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Thomas
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57
votes
3 answers
What is the formula for pi used in the Python decimal library?
(Don't be alarmed by the title; this is a question about mathematics, not programming.)
In the documentation for the decimal module in the Python Standard Library, an example is given for computing the digits of $\pi$ to a given precision:
def…
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ShreevatsaR
- 39,794
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57
votes
2 answers
Books about the Riemann Hypothesis
I hope this question is appropriate for this forum. I am compiling a list of all books about the Riemann Hypothesis and Riemann's Zeta Function.
The following are excluded:
Books by mathematical cranks (especially books by amateurs who claim to…
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Marko Amnell
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57
votes
8 answers
Evaluate $\int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx$
Evaluate
$$\int_0^1\left(\frac{1}{\ln x} + \frac{1}{1-x}\right)^2 \mathrm dx$$
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user 1591719
- 43,176
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57
votes
6 answers
What is the difference between homotopy and homeomorphism?
What is the difference between homotopy and homeomorphism? Let X and Y be two spaces, Supposed X and Y are homotopy equivalent and have the same dimension, can it be proved that they are homeomorphic? Otherwise, is there any counterexample?…
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liufu
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57
votes
2 answers
Is it possible to prove a mathematical statement by proving that a proof exists?
I'm sure there are easy ways of proving things using, well... any other method besides this!
But still, I'm curious to know whether it would be acceptable/if it has been done before?
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chubbycantorset
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57
votes
9 answers
A linear operator commuting with all such operators is a scalar multiple of the identity.
The question is from Axler's "Linear Algebra Done Right", which I'm using for self-study.
We are given a linear operator $T$ over a finite dimensional vector space $V$. We have to show that $T$ is a scalar multiple of the identity iff $\forall S \in…
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abeln
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57
votes
18 answers
Is it possible to determine if you were on a Möbius strip?
I understand that if you were to walk on the surface of a Möbius strip you would have the same perspective as if you walked on the outer surface of a cylinder. However, would it be possible for someone to determine whether they were on a Möbius…
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Steven Wallace
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