Unstable dimension variability: A source of nonhyperbolicity in chaotic systems

Eric Kostelich, Ittai Kan, Celso Grebogi, Edward Ott, James A. Yorke

Research output: Contribution to journalArticlepeer-review

102 Scopus citations


The hyperbolicity or nonhyperbolicity of a chaotic set has profound implications for the dynamics on the set. A familiar mechanism causing nonhyperbolicity is the tangency of the stable and unstable manifolds at points on the chaotic set. Here we investigate a different mechanism that can lead to nonhyperbolicity in typical invertible (respectively noninvertible) maps of dimension 3 (respectively 2) and higher. In particular, we investigate a situation (first considered by Abraham and Smale in 1970 for different purposes) in which the dimension of the unstable (and stable) tangent spaces are not constant over the chaotic set; we call this unstable dimension variability. A simple two-dimensional map that displays behavior typical of this phenomenon is presented and analyzed.

Original languageEnglish (US)
Pages (from-to)81-90
Number of pages10
JournalPhysica D: Nonlinear Phenomena
Issue number1-2
StatePublished - 1997


  • Hyperbolicity
  • Shadowing
  • Stable manifolds

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Mathematical Physics
  • Condensed Matter Physics
  • Applied Mathematics


Dive into the research topics of 'Unstable dimension variability: A source of nonhyperbolicity in chaotic systems'. Together they form a unique fingerprint.

Cite this