8,899 reputation
1646
bio website people.bath.ac.uk/mdp33
location Bath, United Kingdom
age 25
visits member for 2 years, 10 months
seen 2 days ago

Postgraduate student at the University of Bath, UK, studying geometry and representation theory. Currently thinking about cluster algebras and related objects.


Nov
10
comment Smallest Subring of R that contains $S \cup \{a\}$
You seem to be thinking along the right lines. Can you show that any subring $S'$ containing $S\cup\{a\}$ in fact contains the set in question? This is enough to show that your set is contained in the intersection of all subrings containing $S\cup\{a\}$, and the other direction is easy since you have already shown that your set is such a subring.
Nov
10
comment Prove that $(x^3-2)$ is a maximal ideal of $\Bbb Q[x]$
To get better answers, you should add some context to your question - what have you already tried? Do you know some theorems that might help? For example, would it help you to know that $x^3-2$ is irreducible? Can you prove that it is?
Nov
7
comment Proving that $f$ is a bijection.
@egreg I'm not sure I'm following - the OP has a definition ($g(y)=x\iff f(x)=y$) in the question.
Nov
6
comment Proving that $f$ is a bijection.
It doesn't appear to be the definition the OP is using, given the phrasing of both the problem they are trying to solve and the clause beginning "I basically need to show...".
Nov
6
answered Proving that $f$ is a bijection.
Nov
6
answered Semisimple submodule
Nov
6
reviewed Approve I love maths, but my school is limited in its teachings.
Nov
5
comment Give a counterexample to show that $(AB)^{-1} \neq A^{-1}B^{-1}$
To make the same point in another way - it is not true that $AB\ne BA$ for all $A,B$, but there do exist some $A,B$ for which $AB\ne BA$ - so find a pair (that are also invertible), and you have an explicit counterexample.
Nov
5
comment Shape of the visible part of the Moon
Pas de problème. ;) I have just discovered that both of these things are "ellipse" in French, which makes your mistake even more forgivable than it already was!
Nov
5
comment Shape of the visible part of the Moon
Since you asked for language corrections - I'm pretty certain that you meant "ellipse" in "other cases". This is the shape (singular of ellipses), whereas ellipsis refers to the three dots immediately preceding the word!
Nov
5
revised Shape of the visible part of the Moon
deleted 1 character in body
Nov
5
comment re-writing a mathematical expression
@EmmaTebbs I agree this is a slightly difficult question to tag - myself and another user have now retagged it. Physics and matlab are both relevant to the context, and I also added algebra-precalc because it's essentially about manipulating expressions (although the expressions are a little more involved than those that would normally occur under this tag!).
Nov
5
revised re-writing a mathematical expression
edited tags
Nov
5
comment re-writing a mathematical expression
@EmmaTebbs They also use $f$ again in a second expression on the next page, so its more efficient to define it separately. (It also prevents the formula from $K_{\mathrm{int}}$ from breaking over three lines, which would make it harder to read.)
Nov
4
awarded  Nice Answer
Nov
4
comment Can basis vectors have fractions?
@Bill Since my point was that the operation of clearing denominators doesn't make sense in general, it didn't seem worth identifying the most general situation in which it does makes sense.
Nov
4
revised $f(x)=x^p-a$ is either ireducible or has a root?
added 36 characters in body
Nov
4
comment $f(x)=x^p-a$ is either ireducible or has a root?
Your first assertion is false; if $k=\mathbb{R}$ or $k=\mathbb{C}$, then $f$ is not irreducible for most values of $p$, by the fundamental theorem of algebra.
Nov
4
revised Can basis vectors have fractions?
added 134 characters in body
Nov
4
answered Can basis vectors have fractions?