Mikhail Ostrovskii's user avatar
Mikhail Ostrovskii's user avatar
Mikhail Ostrovskii's user avatar
Mikhail Ostrovskii
  • Member for 9 years, 6 months
  • Last seen more than a week ago
23 votes
Accepted

Who proved that $l^1$ and $L^1[0,1]$ are not isomorphic?

11 votes
Accepted

Complemented subspaces constructed from finite pieces- part II

11 votes
Accepted

If a subspace $F$ is contained in a subspace $G$, and $H$ is close to $G$, can we choose a subspace of $H$ close to $F$?

10 votes

In infinite dimensions, is it possible that convergence of distances to a sequence always implies convergence of that sequence?

10 votes
Accepted

Two questions about basic sequences

9 votes
Accepted

Well-complemented copies of $\ell_p^n$

7 votes

Almost isometric embeddability implies isometric embeddability

7 votes

Is X+X finitely representable in X?

6 votes
Accepted

ODE properties true in finite dimension but not in Banach spaces of infinite dimension

6 votes
Accepted

Thin large subspaces of $\ell^N_1$

6 votes

Banach spaces $X$ with $\ell_2(X)$ not isomorphic to $L_2([0,1],X)$

6 votes
Accepted

Location of a Banach Space inside its bidual

6 votes

Antiproximanal subspace of $L_1[0,1]$

6 votes
Accepted

Characterization of operator ranges

6 votes
Accepted

Approximation property of a Banach space in terms of finite-rank projections

6 votes

Differentiability of the map $x\mapsto \delta_x$ in the Arens-Eells/Lipschitz-free space

5 votes
Accepted

If $E\oplus_\phi E \cong E\oplus_\psi E,$ does it imply that $\phi= \psi$?

5 votes
Accepted

example of an $\ell_1$-saturated Banach space without an unconditional basis

5 votes
Accepted

Under what conditions can we put a complete norm on a linear subspace of a separable Banach space?

5 votes
Accepted

Basis equivalent with a monotone basis

4 votes
Accepted

A differential equation with continuous coefficient and no solution in a reflexive Banach space?

4 votes
Accepted

Hermitian Projections on $C[0,1]$

4 votes
Accepted

A Hilbert space characterization via retractions--a conjecture

4 votes

A question on strictly cosingular operators

4 votes

Surface area of an $\ell_p$ unit ball?

4 votes
Accepted

On the complemented subspaces of $L_{p}(p>2)$

4 votes
Accepted

On norming weakly$^*$ sequences in the dual of the Banach space $c_0$

4 votes
Accepted

The anti-symmetric property of the collection of all compact convex sets of a Banach space

4 votes
Accepted

Extending functionals on $X^*$

3 votes
Accepted

Annihilators and pre-annihilators