850 reputation
515
bio website
location
age
visits member for 3 years, 3 months
seen Apr 12 at 10:22

Jul
14
awarded  Notable Question
Jul
2
awarded  Curious
Jun
18
awarded  Yearling
Apr
12
comment $k[x]/(x^n) \otimes_{k[x]} k[y]/(y^m)$
Well start by changing the name of the variable in one side from $x$ to $y$ so it becomes $k[x]\otimes k[y]$
Apr
12
comment One to one mapping from $A(S_1)$ into $A(S_2)$
Elements of $f\in A(S^1)$ are 1-1 functions from $f:S^1\to S^1$ and $\phi:S^1\to S^2$ is 1-1, what can you say about their composition $\phi\circ f$
Mar
26
comment Why is the fibre of each point compact?
The fiber is a closed subset of a compact space hence compact. It is closed because it is the inverse image of the closed set $\{x\}$ by a continuous function.
Mar
25
comment Trivialization of the normal bundle of a knot
@Lepanais Yes the Mobius band is the unique non orientable line bundle over $S^1$.
Mar
24
revised Trivialization of the normal bundle of a knot
added 8 characters in body
Mar
24
revised Trivialization of the normal bundle of a knot
edited body
Mar
24
answered Trivialization of the normal bundle of a knot
Mar
17
revised Prove that $\frac{2^n}{n!}$ converges 0.
added 3 characters in body
Mar
16
comment Example of a non-measurable set of a particular kind
I see now what is the problem, for the a proof that every Riemann integrable function is measurable check folland's book. I think he gives a proof by constructing measurable functions such that $f$ is their pointwise limit.
Mar
16
comment Example of a non-measurable set of a particular kind
This is not possible because there is a theorem called Lebesgue integrability criterion tells you that the set of discontinuities of $f$ are of measure 0 (hence any subset of it is measurable)
Mar
12
answered Lie group, Lie algebra and surjectivity
Mar
4
comment Limit of a function, not using L'Hospital's Rule
This is just the derivative of $f(x)=x^x$ at $a$, to evaluate it write $f(x)=e^{x\log x}.$
Feb
23
comment Topological Entropy of $(x,y)\mapsto(x+y,x+a)$
Can't you edit your answer and add the other solution. I just think it would be better if the two answers were in same place, also thanks for taking some of your time to think about the problem.
Feb
23
accepted Topological Entropy of $(x,y)\mapsto(x+y,x+a)$
Feb
23
comment Topological Entropy of $(x,y)\mapsto(x+y,x+a)$
Thanks a lot for your answer, but what about the map $(x,y)\to (x+y,y+a)$ in this case $A$ is not hyperboloic. Can we use similar method in this case?
Feb
23
revised Topological Entropy of $(x,y)\mapsto(x+y,x+a)$
edited title
Feb
23
asked Topological Entropy of $(x,y)\mapsto(x+y,x+a)$