User Mikhail Ostrovskii - MathOverflow

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Mikhail Ostrovskii

Member for 9 years, 10 months
Last seen more than a month ago

facpub.stjohns.edu/ostrovsm
New York, United States

61 Answers

Score Activity Newest

23 votes

Accepted

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

answered May 4, 2016 at 3:38

11 votes

Accepted

Complemented subspaces constructed from finite pieces- part II

answered Dec 25, 2018 at 2:08

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 $F$?

answered Dec 17, 2020 at 1:52

10 votes

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

answered Jul 24, 2020 at 5:52

10 votes

Accepted

Two questions about basic sequences

answered Apr 14, 2018 at 6:28

9 votes

Accepted

Well-complemented copies of $\ell_p^n$

answered Aug 11, 2015 at 21:42

7 votes

Almost isometric embeddability implies isometric embeddability

answered Jun 16, 2015 at 17:19

7 votes

Is X+X finitely representable in X?

answered Nov 19, 2016 at 16:32

6 votes

Accepted

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

answered Jan 12, 2015 at 3:34

6 votes

Accepted

Thin large subspaces of $\ell^N_1$

answered Nov 20, 2015 at 16:43

6 votes

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

answered Dec 2, 2015 at 21:21

6 votes

Accepted

Location of a Banach Space inside its bidual

answered Apr 10, 2015 at 5:12

6 votes

Antiproximanal subspace of $L_1[0,1]$

answered Jan 13, 2016 at 5:25

6 votes

Accepted

Characterization of operator ranges

answered May 22, 2019 at 3:03

6 votes

Accepted

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

answered Dec 9, 2019 at 18:40

6 votes

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

answered Jul 13, 2021 at 20:13

5 votes

Accepted

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

answered Aug 7, 2018 at 21:30

5 votes

Accepted

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

answered Dec 7, 2015 at 15:21

5 votes

Accepted

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

answered Dec 10, 2015 at 23:30

5 votes

Accepted

Basis equivalent with a monotone basis

answered Apr 3, 2015 at 12:49

4 votes

Accepted

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

answered Jun 27, 2015 at 20:44

4 votes

Accepted

Hermitian Projections on $C[0,1]$

answered Jan 14, 2016 at 11:20

4 votes

Accepted

A Hilbert space characterization via retractions--a conjecture

answered Dec 31, 2015 at 20:13

4 votes

A question on strictly cosingular operators

answered Nov 22, 2016 at 16:09

4 votes

Surface area of an $\ell_p$ unit ball?

answered Mar 30, 2016 at 17:27

4 votes

Accepted

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

answered Jun 1, 2016 at 1:51

4 votes

Accepted

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

answered Jun 4, 2019 at 4:43

4 votes

Accepted

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

answered Jan 8, 2017 at 0:42

4 votes

Accepted

Extending functionals on $X^*$

answered Mar 29, 2017 at 4:26

3 votes

Accepted

Annihilators and pre-annihilators

answered Apr 5, 2017 at 16:16

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