Zapiski Nauchnykh Seminarov POMI
RUS  ENG    JOURNALS   PEOPLE   ORGANISATIONS   CONFERENCES   SEMINARS   VIDEO LIBRARY   PACKAGE AMSBIB  
General information
Latest issue
Archive
Impact factor

Search papers
Search references

RSS
Latest issue
Current issues
Archive issues
What is RSS



Zap. Nauchn. Sem. POMI:
Year:
Volume:
Issue:
Page:
Find






Personal entry:
Login:
Password:
Save password
Enter
Forgotten password?
Register


Zapiski Nauchnykh Seminarov POMI, 2013, Volume 415, Pages 24–28 (Mi znsl5682)  

On the space of convex figures

V. V. Makeev, N. Yu. Netsvetaev

St. Petersburg State University, St. Petersburg, Russia
References:
Abstract: Let $T$ be the set of convex bodies in $\mathbb R^k$, and let $\mathcal T$ be the set of classes of similar bodies in $T$. We write $F$ for $T$ in the case $k=2$. Define a metric $d$ on $\mathcal T$ by setting for classes $\{K_1\},\{K_2\}$ (from $\mathcal T$, of convex bodies $K_1,K_2$) $d(\{K_1\},\{K_2\}) =\inf\{\ln(b/a)\}$, where $a$ and $b$ are positive reals such that there is a similarity transformation $A$ with $aA(K_1)\subset K_2\subset bA(K_1)$. Let $D_2$ be a planar unit disk. If $x>0$, we denote by $F_x$ the set of the planar convex figures $K$ in $F$ with $d(\{D_2\},\{K\})\ge x$. We also equip the sets $T$ and $F$ with the usual Hausdorff metric.
We prove that if $y>\ln(\operatorname{sec}(\pi/n))\ge x$ for some integer $n>2$, then no mapping $F_x\to F_y$ is $\operatorname{SO}(2)$-equivariant.
Let $M_k (n)$ be the space of $k$-dimensional convex polyhedra with at most $n$ hyperfaces (vertices), and let $M_k$ denote the space of $k$-dimensional convex polyhedra. We prove that there are no $\operatorname{SO}(2)$-equivariant continuous mappings $M_k(n+k)\to M_k(n)$.
Let $T^s$ be the closed subspace of $T$ formed by centrally symmetric bodies. Let $T_x$ denote the closed subspace of $T$ formed by the bodies $K$ with $d(T^s,\{K\})\ge x>0$. We prove that for every $y>0$ there exists an $x>0$ such that no mapping $T_x\to T_y$ is $\operatorname{SO}(2)$-equivariant.
Key words and phrases: convex figure, convex body, orthogonal group, vector bundle, Grassmannian.
Received: 31.12.2012
English version:
Journal of Mathematical Sciences (New York), 2016, Volume 212, Issue 5, Pages 533–535
DOI: https://doi.org/10.1007/s10958-016-2682-8
Bibliographic databases:
Document Type: Article
UDC: 514.172
Language: Russian
Citation: V. V. Makeev, N. Yu. Netsvetaev, “On the space of convex figures”, Geometry and topology. Part 12, Zap. Nauchn. Sem. POMI, 415, POMI, St. Petersburg, 2013, 24–28; J. Math. Sci. (N. Y.), 212:5 (2016), 533–535
Citation in format AMSBIB
\Bibitem{MakNet13}
\by V.~V.~Makeev, N.~Yu.~Netsvetaev
\paper On the space of convex figures
\inbook Geometry and topology. Part~12
\serial Zap. Nauchn. Sem. POMI
\yr 2013
\vol 415
\pages 24--28
\publ POMI
\publaddr St.~Petersburg
\mathnet{http://mi.mathnet.ru/znsl5682}
\transl
\jour J. Math. Sci. (N. Y.)
\yr 2016
\vol 212
\issue 5
\pages 533--535
\crossref{https://doi.org/10.1007/s10958-016-2682-8}
\scopus{https://www.scopus.com/record/display.url?origin=inward&eid=2-s2.0-84959162967}
Linking options:
  • https://www.mathnet.ru/eng/znsl5682
  • https://www.mathnet.ru/eng/znsl/v415/p24
  • Citing articles in Google Scholar: Russian citations, English citations
    Related articles in Google Scholar: Russian articles, English articles
    Записки научных семинаров ПОМИ
    Statistics & downloads:
    Abstract page:219
    Full-text PDF :51
    References:33
     
      Contact us:
     Terms of Use  Registration to the website  Logotypes © Steklov Mathematical Institute RAS, 2024