Reputation
4,164
Next privilege 5,000 Rep.
Approve tag wiki edits
Badges
1 20 54
Impact
~211k people reached

Jan
22
awarded  Popular Question
Jan
19
accepted Is the metric on the circle, induced from the plane, not a flat one?
Jan
13
comment Is the metric on the circle, induced from the plane, not a flat one?
Not sure if I follow. Whatever the value of the distance between two point, the metrics are still flat right?
Jan
13
answered Let $f(x) = (x^n-1)/(x-1)$. Why does $f(1)=n$?
Jan
13
revised Is the metric on the circle, induced from the plane, not a flat one?
added 3 characters in body
Jan
13
asked Is the metric on the circle, induced from the plane, not a flat one?
Dec
29
comment What is the $\tau$ symbol in the Bourbaki text?
Thank you! If $(\exists x)R$ is alias for $R[\tau_x(R)]$, then what if $(\exists x)R$ is actually false? You imply $\tau_x(R)$ still makes sense then.
Dec
22
revised A question on concrete category
edited body
Dec
5
comment Power series representation of $\frac{1+x}{1-x}$ explanation?
Remark: Note that your $\frac{1}{x}$-move spoils the possibility to evaluate your sum representation for $\frac{1+x}{1-x}$ at $x=0$. Similat story for $\lim_{x\to\infty}$. Simulatnously, the naive termwise substraction of infinite sums makes each $x^n-\frac{1}{x^n}$ well defined at $x=1$, whereas $\frac{1+x}{1-x}$ is not.
Dec
5
answered A question on concrete category
Dec
4
awarded  Popular Question
Nov
27
comment Pullbacks - question 5.7.2 from Awodey's *Category Theory*
Btw. I asked a semi-related question here here.
Nov
27
comment Pullbacks - question 5.7.2 from Awodey's *Category Theory*
For sure you want to add to the square in the second question (with corners being $X, A, B$ and $A\times_X B$) an arrow $f:Y\to X$. What's eventually asked for is supposed to be a pullback square over $Y$. Ask yourself: What are ways in which the 3 remaining corners could be obtained from the 5 you already got? For the last part, think about what you start with (the diagram in that question) and what you're supposed to use (the diagram in the first question). Use the result of the second to bridge the two.
Nov
27
comment Let $f_n(x) =\frac{x}{1+nx^2}$ and what function does this sequence converge to?
How come you asked 50 questions on Math SE but don't know the basics of formatting here?
Nov
27
comment Is $0.999999999… = 1$?
$\neg\neg P\implies P$, yikes.
Nov
14
revised Why is there no explicit formula for the factorial?
added 108 characters in body
Nov
14
answered Why is there no explicit formula for the factorial?
Nov
6
awarded  Yearling
Nov
6
awarded  Notable Question
Sep
11
comment What is the appropriate method to find the value of $1$ - $1\over 7$ + $1\over 13$ - … upto infinite terms?
Seems like all sums over $\dfrac{z^n}{(n+\alpha)^\color{red}{1}}$ can be solved like this. Is the Lerch transcendent always manageable when the red number (power of the denominator) is 1? Mathematica gives nice functions in $z$ for all integer $\alpha$ I tried.