Abstract
Let T be an aperiodic automorphism of a standard probability space (X,m). Let P be the subset of A=L ∞(X, Sl(2, R)) where the upper Lyapunov exponent is positive almost everywhere.
We prove that the set P∖int(P) is not empty. So, there are always points in A where the Lyapunov exponents are discontinuous.
We show further that the decision whether a given cocycle is in P is at least as hard as the following cohomology problem: Can a given measurable set Z ⊂ X be represented as YΔT(Y) for a measurable set Y ⊂ X?
Keywords
- Lyapunov Exponent
- Invariant Measure
- Exponential Dichotomy
- Ergodic Measure
- Positive Lyapunov Exponent
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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© 1991 Springer-Verlag
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Knill, O. (1991). The upper Lyapunov exponent of Sl(2,R) cocycles: Discontinuity and the problem of positivity. In: Arnold, L., Crauel, H., Eckmann, JP. (eds) Lyapunov Exponents. Lecture Notes in Mathematics, vol 1486. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0086660
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DOI: https://doi.org/10.1007/BFb0086660
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