Sibirskii Matematicheskii Zhurnal
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



Sibirsk. Mat. Zh.:
Year:
Volume:
Issue:
Page:
Find






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


Sibirskii Matematicheskii Zhurnal, 2011, Volume 52, Number 6, Pages 1346–1356 (Mi smj2279)  

On the sectionwise connectedness of a contingent

S. P. Ponomarev, M. Turowska

Institute of Mathematics, Pomeranian Academy in Słupsk, Słupsk, Poland
References:
Abstract: Let $X$ be a real normed space and let $f\colon\mathbb R\to X$ be a continuous mapping. Let $\mathrm T_f(t_0)$ be the contingent of the graph $G(f)$ at a point $(t_0,f(t_0))$ and let $S^+\subset(0,\infty)\times X$ be the “right” unit hemisphere centered at $(0,0_X)$. We show that
1. If $\dim X<\infty$ and the dilation $D(f,t_0)$ of $f$ at $t_0$ is finite then $\mathrm T_f(t_0)\cap S^+$ is compact and connected. The result holds for $\mathrm T_f(t_0)\cap\overline{S^+}$ even with infinite dilation in the case $f\colon[0,\infty)\to X$.
2. If $\dim X=\infty$, then, given any compact set $F\subset S^+$, there exists a Lipschitz mapping $f\colon\mathbb R\to X$ such that $\mathrm T_f(t_0)\cap S^+=F$.
3. But if a closed set $F\subset S^+$ has cardinality greater than that of the continuum then the relation $\mathrm T_f(t_0)\cap S^+=F$ does not hold for any Lipschitz $f\colon\mathbb R\to X$.
Keywords: contingent (tangent cone), dilation, connectedness, compactness, Euclidean space, cardinality.
Received: 18.11.2010
English version:
Siberian Mathematical Journal, 2011, Volume 52, Issue 6, Pages 1069–1078
DOI: https://doi.org/10.1134/S0037446611060127
Bibliographic databases:
Document Type: Article
UDC: 517.98.22
Language: Russian
Citation: S. P. Ponomarev, M. Turowska, “On the sectionwise connectedness of a contingent”, Sibirsk. Mat. Zh., 52:6 (2011), 1346–1356; Siberian Math. J., 52:6 (2011), 1069–1078
Citation in format AMSBIB
\Bibitem{PonTur11}
\by S.~P.~Ponomarev, M.~Turowska
\paper On the sectionwise connectedness of a~contingent
\jour Sibirsk. Mat. Zh.
\yr 2011
\vol 52
\issue 6
\pages 1346--1356
\mathnet{http://mi.mathnet.ru/smj2279}
\mathscinet{http://mathscinet.ams.org/mathscinet-getitem?mr=2961760}
\transl
\jour Siberian Math. J.
\yr 2011
\vol 52
\issue 6
\pages 1069--1078
\crossref{https://doi.org/10.1134/S0037446611060127}
\isi{https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=Publons&SrcAuth=Publons_CEL&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=000298650800012}
\scopus{https://www.scopus.com/record/display.url?origin=inward&eid=2-s2.0-84855181482}
Linking options:
  • https://www.mathnet.ru/eng/smj2279
  • https://www.mathnet.ru/eng/smj/v52/i6/p1346
  • Citing articles in Google Scholar: Russian citations, English citations
    Related articles in Google Scholar: Russian articles, English articles
    Сибирский математический журнал Siberian Mathematical Journal
     
      Contact us:
     Terms of Use  Registration to the website  Logotypes © Steklov Mathematical Institute RAS, 2025