Reputation
Next tag badge:
397/400 score
88/80 answers
Badges
13 175 333
Impact
~2.0m people reached

14h
revised Confused with the power set of an integer
added 3 characters in body
14h
comment Confused with the power set of an integer
If $\Bbb P$ denotes power set, isn't it strange that these are multiplied and compared?
14h
answered Confused with the power set of an integer
14h
answered are two metrics with same compact sets topologically equivalent?
14h
answered A man has to paint n consecutive mile posts and wants to do this as inefficiently as possible…
15h
answered Use of implicit function theorem in showing that $f(x) \leq a$ is a submanifold with boundary
18h
answered Countable connected spaces
18h
answered Field characteristic for a finite product of fields of characteristic $0$
19h
revised Lower bound of multinomial coefficients?
added 29 characters in body
19h
answered Lower bound of multinomial coefficients?
19h
comment How can I prove that G is abelian?
@IvanS.Guerra I only claim that $N$ is contained in $Z(G)$. For any $a\in N$, the inner automorphism $x\mapsto axa^{-1}$ has order dividing $|N|$ and order dividing $|\operatorname{Inn}(G)|$, hence dividing $(n,m)=1$. We conclude that $x\mapsto axa^{-1}$ is the identity, i.e.,, $a\in N$ commutes with all $x\in G$.
19h
revised Given the sequence of functions, $f_1(x):=\sin(x)$ and $f_{n+1}(x):=\sin(f_n(x))$, why $|f_n(x)|\leq f_n(1)$?
added 29 characters in body
19h
answered Given the sequence of functions, $f_1(x):=\sin(x)$ and $f_{n+1}(x):=\sin(f_n(x))$, why $|f_n(x)|\leq f_n(1)$?
19h
revised How can I prove that G is abelian?
added 30 characters in body
19h
answered How can I prove that G is abelian?
20h
comment Is this limit indeterminate or $e^2$ or what?
The fact that "naive" computation of the limit leads to an indeterminate form does not prevent the limit from possibly existing. For example, $\lim_{x\to 0}\frac{\sin x}{x}$ is also indeterminate of form $\frac 00$, but the limit exists.
20h
comment Linear Algebra. Is this question realte to combination and factorials?
For example with $n=3$, $$A=\begin{pmatrix}2\choose 1&3\choose 1&4\choose1\\3\choose2&4\choose 2&5\choose 2\\4\choose3&5\choose 3&6\choose 3\end{pmatrix}=\begin{pmatrix}2&3&4\\3&6&10\\4&10&20\end{pmatrix} $$
1d
comment Regarding the iteration of sum of prime factors
@user1952009 Don't you rather mean the twin prime conjecture?
1d
comment Can sum of rationals be irrational?
A series is not a sum.
1d
answered It is true that $rank(xy^T)=1$?