Homepage of Henryk Michalewski
I am a topologist and I work at the Institute of Mathematics, University of
Warsaw. Currently, between September 2005 and September 2006, I am a postdoc at Ben Gurion University in Israel.
Between 1998 and 2002 I studied as a PhD student under supervision of
Witold Marciszewski.
Here is a picture (52kB)
from Toposym 2001, which shows my supervisor
and me.
Information on Scientific Research
- Research Interest:
general topology, set theory, abstract functional analysis
(click
here for a postscript file with details).
-
Curriculum Vitae:
postscript file
and
PDF file.
Master thesis: Przestrzenie funkcji ciaglych i
przestrzenie dziedzicznie Baire'a (in Polish; Function spaces
and hereditary Baire spaces).
Supervised by Witold Marciszewski. Defended in 1998.
Doctoral thesis: Przestrzenie funkcyjne
z topologia zbieznosci punktowej
(in Polish; Function spaces with topology of
pointwise convergence).
Supervised by Witold Marciszewski. Given to the referees on March 15th
2002 ( postscript file with my thesis ).
Defended January 9th 2003.
Publications
[a part of them downloadable in the form of postscript files]
-
On a Hurewicz-type theorem and a
selection theorem of Michael, joint paper with Roman Pol,
Bull. Pol. Acad. Sci. 43 (1996),
273-275.
We proved a generalization of Kechris-Louveau-Woodin theorem via
an application of a theorem of Michael on selections.
- Game--theoretic approach to the hereditary
Baire property of $C_p({\mathbb N}_F)$,
Bull. Pol. Acad. Sci. 46 (1998),
135-140.
I gave a
characterization in terms of topological games of these
countable spaces $X$ with one non--isolated point, such that
the function space $C_p(X)$ is a hereditary Baire space (every
closed subset satisfies the Baire Category Theorem). It is a part of my
master degree thesis.
-
Homogeneity of K(Q),
Tsukuba Journ. of Math. 24 (2000), 297--302.
I proved that all separable, metrizable, zero--dimensional spaces
which are of the first category in itself and which are locally coanalytic
complete, are homeomorphic. As a corollory I proved that
the space of all compact
subspaces of rationals, endowed with Hausdorff metric, is a topological
group.
-
An answer to a question of Arkhangelskii,
Comment. Math. Univ. Carolinae 42 (2001)
I gave two examples of a space with the property that
the spaces $C_p(X)$ and $C_p(X\times\omega)$ are linear homeomorphic, but
the spaces $C_p(X)$ and $C_p(X\times(\omega+1))$ are not linear
homeomorphic, where $\omega$ and $\omega+1$ are countable ordinals equiped
with ordinal topology. One of the examples is a metrizable space (it is so
called the Stone space ).
-
An example of a topological group,
joint work with Adam Krawczyk, Topology and its Applications 127 (2003),
pp.325-330.
We consider notions of o-boundedness and strong o-boundedness,
introduced by Tkachenko and Okunev, which generalize
the notion of $\sigma$-compactness in the class of topological groups. We
gave an example of a topological group which is a Lindelof P-space, but
which is not strongly o-bounded.
-
Linear metric spaces
close to being $\sigma$--compact,
joint work with Adam Krawczyk.
We shown, under an additional set theorethical assumption
implied by MA, an example of two o-bounded, metrizable, separable topological
groups, such that their product is not o-bounded. This construction
appeals to the affinity between the o-bounded property and
Menger property of a given topological group.
-
On condensations of projective sets onto
compacta,
Proc. Amer. Math. Soc. 131 (2003) no. 11, pp.3601-3606.
I proved that every coanalytic-complete, separable, metrizable
space might be bijectively, continuously mapped onto the Hilbert cube.
As a corollary I noticed
that the space $C_p(A)$ admits a weaker compact topology if $A$ is
an analytic, separable, metrizable space. For sigma-compact $A$
this result was proved earlier by Arkhangelskii.
-
Functions equivalent
to Borel measurable ones,
joint work with Andrzej Komisarski and Pawel Milewski.
Under additional assumption of Analytic Determinacy we gave
some conditions on a given function $f:R->R$ ($R$ stands for the real
line), which are necessary and sufficient for existence
of a Borel-measurable function equivalent, in a sense
defined by Ryll-Nardzewski and Morayne, to the function $f$.
-
Bourgain-Fremlin-Talagrand Dichotomy and dynamical systems ,
joint work with Andrzej Komisarski and Pawel Milewski.
For a given continuous function $f:[0,1]\to [0,1]$ we give a necessary and
sufficient condition that the closure of subsequent iterations
$f^n$ (n - natural number) in the Tychonoff cub $[0,1]^[0,1]$ is metrizable.
It gives an answer to a question of Gilles Godefroy from 2002.
Our reasoning appeared to be a re-discovery of a result of Angela
Koehler from 1994.
-
Small Valdivia compact space,
joint work with Wieslaw Kubis, accepted to Top.Appl.
Under certain conditions we show that retractions and open images of
Valdivia compact spaces remain Valdivia. In general, as was proved by Kubis and
Uspeinski, open image of a Valdivia compact space may be not Valdivia.
The Summer School in Szumin!
Zajecia z analizy funkcjonalnej 2004/2005
Zajecia z analizy matematycznej 2004/2005
Program seminarium Zakladu Topologii
This page is hosted at
Instytut Matematyki UW, Warsaw.