s.harp's user avatar
s.harp's user avatar
s.harp's user avatar
s.harp
  • Member for 9 years, 9 months
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37 votes
Accepted

Function that is the sum of all of its derivatives

25 votes
Accepted

Is the convex hull of a compact set compact?

24 votes
Accepted

Show that an open linear map between normed spaces is surjective.

13 votes
Accepted

How to show that the fabius function is nowhere analytic?

11 votes
Accepted

Can we say that $\det(A+B) = \det(A) + \det(B) +\operatorname{tr}(A) \operatorname{tr}(B) - \operatorname{tr}(AB)$?

10 votes
Accepted

If $f$ is not continuous then $\ker f$ is dense in $X$

9 votes
Accepted

Summation of reciprocals

9 votes
Accepted

Whenever $f=T(x)$ then $f(x) \geq 0$. Prove $T$ is bounded by closed graph theorem.

8 votes

Does every inner product space have Hilbert completion?

8 votes
Accepted

Banach space with respect to two norms must be Banach wrt the sum of the norms?

7 votes
Accepted

A map between Banach spaces is continuous

7 votes

Why is $\text{Homeo}_p(X)$ not a topological group for $X = \mathbb{R}^2$?

6 votes

Showing the support of a sheaf may not be closed (Liu 2.5)

6 votes
Accepted

Is the Trace of products of Hilbert-Schmidt Operators stable under cyclic permutations?

6 votes
Accepted

Two exercises in functional analysis.

6 votes
Accepted

Measures converging weakly to Dirac delta function

6 votes
Accepted

Is every Pre-Hilbert space reflexive?

5 votes
Accepted

Two Banach spaces, if and only if criterion for range of closed unbounded operator to be closed?

5 votes
Accepted

Norm of a character in a non-unital Banach algebra without approximate identity

5 votes
Accepted

Adjoint of a bounded linear operator is bounded

5 votes
Accepted

Convergence of $A_nT$ to $AT$ in operator norm for compact $T$

5 votes
Accepted

Free $C^*$-Algebras

5 votes
Accepted

Is $(I \circ A - I \circ B)$ positive semi-definite if $A$, $B$ and $A - B$ are positive semi-definite?

5 votes

Determine the lie algebra of the subgroup of SO(4)

5 votes
Accepted

Looking for a function that is continuous but not sequentially weakly continuous

5 votes

The norm of the difference of two projections in a C$^\ast$-algebra

4 votes
Accepted

homomorphisms of B(H)

4 votes
Accepted

Conformal Group when p+q>3

4 votes
Accepted

Net in $\mathcal{B}^*$ converging to unbounded functional

4 votes

$X$ Banach space, and $A: X \rightarrow X'$ is a lineal operator. If $(Ax)(y)=(Ay)(x)$ prove that $A$ is a continuous operator.

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