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PhD student of Mathematics


Aug
9
comment Examples of $C^2(0,1)\cap C[0,1]$
@Tomás, I mean show why $u\in C^2(0,1)\cap C[0,1]$ but not in $C^2[0,1]$.
Aug
8
asked Proof that this function is bounded
Aug
8
accepted How are $C^0,C^1$ norms defined
Aug
8
comment How are $C^0,C^1$ norms defined
@PeterTamaroff, I think so. How about $C^1$
Aug
8
asked How are $C^0,C^1$ norms defined
Aug
8
comment Examples of $C^2(0,1)\cap C[0,1]$
Could you show me why this is the case.
Aug
8
comment Examples of $C^2(0,1)\cap C[0,1]$
@Tomas: Could you show me why this is the case
Aug
8
asked Examples of $C^2(0,1)\cap C[0,1]$
Aug
6
revised To evaluate error of singular perturbation problem using green functions
added 11 characters in body; edited tags; edited title
Aug
6
asked Etablishing a bound for derivativces
Aug
6
revised A problem with bounds of derivatives
added 33 characters in body
Aug
6
asked A problem with bounds of derivatives
Aug
5
comment Question of derivatives
I think you need to provide cases before you say " Therefore $\psi(x)−\psi(x^\ast)$ assumes as well positive as negative values in the immediate neighborhood of $x^\ast$". Could this proof have been easy with $r$ spelt out. I am confused. Can you consider a proof without this sgn?
Aug
5
comment Question of derivatives
I am a bit lost with your reasoning. I dont get sgn$(\psi(x)-\psi(x^\ast))=$sgn$(c)$.sgn$(x-x^\ast)$. What is it used for? Shoud you not consider the sign of $r(x)$ in $sgn(\psi(x)-\psi(x\ast))$=sgn$(c)$.sgn$(x-x\ast)$? Also is $x>x^\ast$? I also dont see how $\psi$ would not even have a local minimum at x∗, let alone a global minimum.
Aug
3
comment Boundedness of derivaticves
could you give reference to the proof.
Aug
3
comment Boundedness of derivaticves
@DanielFischer, thanks I had omitted the condition on $b$. How can I prove this or which theorem is used to justify the claim.
Aug
3
revised Boundedness of derivaticves
added 54 characters in body
Aug
3
asked Boundedness of derivaticves
Aug
3
comment Question of derivatives
@GEdgar, $\Omega$ is now defined.
Aug
3
revised Question of derivatives
added 16 characters in body