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Dec
1
answered Removing noise when the signal is not smooth
Dec
1
comment simple statement proof
@doniyor: in that case, every question on this site should have the [set-theory] tag. [set-theory] is about ZFC and such.
Dec
1
comment Cat Dog problem using integration
+1 for a lot of effort. if i could give +3 i would.
Nov
30
comment Real world applications of prime numbers?
Note that this encryption system will be utterly useless as soon as quantum computers are reasonably usable.
Nov
30
comment $f: V \mapsto V$ is a projection, show $V = \ker(\pi) \oplus \operatorname{Im}(\pi)$
Your map $v\mapsto(v-f(v),f(v))$ is a good one. Is it a linear space? What is its dimension?
Nov
30
comment $f: V \mapsto V$ is a projection, show $V = \ker(\pi) \oplus \operatorname{Im}(\pi)$
In that case you haven't proven that $\ker(\pi)+\operatorname{im}(\pi)=\ker(\pi)\oplus\operatorname{im}(\pi)$, only $\ker(\pi)\cap\operatorname{im}(\pi)\subset\ker(\pi)+\operatorname{im}(\pi)$
Nov
30
comment $f: V \mapsto V$ is a projection, show $V = \ker(\pi) \oplus \operatorname{Im}(\pi)$
Please put your entire equation in the math environment, not just the extra symbols you need. So write \$\pi\circ\pi=\pi\$ instead of \$\pi\$o\$\pi\$=\$\pi\$.
Nov
30
comment $f: V \mapsto V$ is a projection, show $V = \ker(\pi) \oplus \operatorname{Im}(\pi)$
What do you mean by $\ker(\pi)+im(\pi)$? Do you mean $\ker(\pi)\oplus im(\pi)$? In that case, equivalence is not clear to me.
Nov
30
comment $f: V \mapsto V$ is a projection, show $V = \ker(\pi) \oplus \operatorname{Im}(\pi)$
A rather quick method would be using the exact sequence $0\to\ker f\to V\to V/\ker f\to0$.
Nov
30
comment $f: V \mapsto V$ is a projection, show $V = \ker(\pi) \oplus \operatorname{Im}(\pi)$
"So v = (v - π(v)) + π(v) is in Ker(π) + Im(π)." Please explain.
Nov
29
comment Convergence on open-minus-countable topology
What have you tried?
Nov
29
comment how to calculate the fundamental group using intitutive ideas?
@hina: what is unclear.
Nov
29
comment how to calculate the fundamental group using intitutive ideas?
@QiaochuYuan: I don't think so. isn't the fundamental group of what you're saying isomorphic to Z? I don't think hina's group is...
Nov
27
comment How can I find this result modulo $10^8$?
if $N$ is much smaller than $a$, your square root is approximately equal to just $2a+1$.
Nov
27
comment Solve $x^2(1-x) = 1$
There is only one real solution, there are two complex solutions. See wolframalpha.com/input/?i=solve+x%5E2%281%E2%88%92x%29%3D1
Nov
27
comment How to Integrate along a path
Trying to save one more unupvoted answer from doom.
Nov
27
comment proving homeomorphism
This answer is correct, but of course the formula you gave is not very helpful - I mean sure, it is right, but how'd you get it? Surely you can shed some light on that.
Nov
27
comment $R\neq R[x]$ if $R$ be Noether ring
You clearly did not learn from the comments to your previous questions. Please add your own work and attempts, and don't use the imperative "show".
Nov
24
comment Is mathematics the only language that is not subject of interpretation?
@tomasz: ugh, no, the language of mathematics is not explained in every single paper or a mathematical subject. but that is of course not the point that I was trying to make :-/
Nov
23
comment Limit of sequences
@yuta, well, do you have a definition for convergence? What have you tried to prove the statements?