Reputation
11,088
Top tag
Next privilege 15,000 Rep.
Protect questions
Badges
2 22 48
Impact
~219k people reached

Jul
6
comment Show that$ f(x)=x^5-3$ is solvable by radicals over $\mathbb{Q}$.
What about inserting $3^{1/5}$ and observing that you get $0$?
Jul
6
revised Why don't we define division by zero as an arbritrary constant such as $j$?
added the name of the structure
Jul
6
comment Why don't we define division by zero as an arbritrary constant such as $j$?
@FlybyNight: See the second link in my answer. I've now added the explicit name in the text.
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@BrianRushton: Your link is to a Google search. Which of the many links (which almost certainly show up in different order for me than for you) is the one you're talking about?
Jul
6
comment Why don't we define division by zero as an arbritrary constant such as $j$?
Actually, even $0/0$ is defined in wheels.
Jul
6
answered Why don't we define division by zero as an arbritrary constant such as $j$?
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@CameronWilliams: There are surely many different ways to define Euclidean spaces. However I'm specifically interested to do it from the metric.
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@CameronWilliams: So how do you define "all norms" if all you have is a set $M$ and a single(!) function $d\colon M\times M\to M$?
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@ClementC.: Strange, now your first link works. Must have been a temporary server problem. Anyway, even your second link is not what I want because it also refers to an additional structure, namely the Euclidean vector space defined in your first link.
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@ChrisEagle: OK, now corrected. Thank you.
Jul
6
revised When is a metric space Euclidean, without referring to $\mathbb R^n$?
Fixed a mistake in (U)
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@ChrisEagle: Oops, you're right; I've forgotten a crucial condition ... I'll correct.
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@ChrisEagle: Could you please give me a concrete counter example?
Jul
6
comment When is a metric space Euclidean, without referring to $\mathbb R^n$?
@ClementC.: According top your link, it is "page not found" ;-) But anyway, my point was that I wanted to use only the metric.
Jul
6
asked When is a metric space Euclidean, without referring to $\mathbb R^n$?
Jul
6
comment How to embed Klein Bottle into $R^4$
@Y.Fan: I can't see $y/2$ anywhere. So I'd say it's period $4\pi$ in $x$ and $2\pi$ in $y$.
Jul
6
revised What is the group $\langle U, * \rangle$ where $U$ is the set of roots of unity and * is normal multiplication?
added 137 characters in body
Jul
6
answered What is the group $\langle U, * \rangle$ where $U$ is the set of roots of unity and * is normal multiplication?
Jul
6
comment What is the group $\langle U, * \rangle$ where $U$ is the set of roots of unity and * is normal multiplication?
The dot is created with \cdot.
Jul
6
comment What is the group $\langle U, * \rangle$ where $U$ is the set of roots of unity and * is normal multiplication?
Is $*$ supposed to be the normal multiplication? Normally if you mean that, you'd write $\cdot$ or $\times$; $*$ usually hints at a special multiplication which is different from the normal one.