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Mar
16
awarded  Popular Question
Mar
7
comment Intersection of all neighborhoods of zero is a subgroup
@TobiasKildetoft Thank you for your comment!
Feb
27
awarded  Nice Question
Feb
26
awarded  Famous Question
Feb
20
comment Are these linear maps bounded?
Seriously: first you pretend you can solve the exercise by "giving" "overgenerous hints" and when I press you for an answer you admit you can't solve it either.
Feb
20
comment Are these linear maps bounded?
I think is clear that the idea of the exercise is to give an explicit example.
Feb
20
comment Are these linear maps bounded?
What's an example of an oscillating function with compact support?
Feb
20
comment Are these linear maps bounded?
Yes, I would like to see an example of a sequence of $f_n$ with $\|f_n\|_\infty \le 1$ and $\|f_n'\|_\infty$ unbounded. Because that's what I've been trying to construct for the past 30 minutes but have not managed. I believe this is what's difficult about this exercise.
Feb
19
comment Are these linear maps bounded?
I also rolled back an entirely unnecessary edit.
Feb
19
revised Are these linear maps bounded?
rolled back to a previous revision
Feb
19
comment Are these linear maps bounded?
I upvote in order to compensate for the spite downvote.
Feb
15
awarded  Nice Answer
Feb
14
comment Hilbert space structure on $C^{*}$ algebras
@JonasMeyer Interesting. Please could you elaborate on your comment?
Feb
14
answered Strictly convex iff norm is strictly sub additive
Feb
11
comment Conditions for Real and Complex Inner Product Spaces
@Jamil_V What operations define $\langle\cdot,\cdot\rangle_r$ depends on what operations define $\langle\cdot,\cdot\rangle$ since $\langle\cdot,\cdot\rangle_r$ is defined to be the real part of $\langle\cdot,\cdot\rangle$. If $E$ is the space $L^2$ then the definition of $\langle\cdot,\cdot\rangle$ involves an integral. But since you don't have more information about $E$ you cannot say more about $\langle\cdot,\cdot\rangle_r$.
Feb
9
answered Conditions for Real and Complex Inner Product Spaces
Feb
6
awarded  Popular Question
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6
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Jan
26
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Jan
16
comment If a sequence of points approaches a convex compact set, then the limit of Cesàro means is in the set
What's a realtion?