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A $C^1$ counterexample to Shub’s entropy conjecture
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Category:Dynamical systems and ergodic theory Lean version:YES! ✔
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A C1 counterexample to the entropy conjecture. Constructs a noninvertible C1 self-map of a compact smooth manifold with zero topological entropy but eigenvalue 2 on second homology. This disproves the homological entropy lower bound for general C1 self-maps: homological growth need not force positive orbit complexity.

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released 2026-09-25  |  1 theorem · 7 lemmas · 12 proofs · 6,617 words  |  PLAY LEVEL 1 »  (pdf)
We disprove the general C1 self-map formulation of Shub's entropy conjecture. We construct a noninvertible C1 self-map of a compact smooth manifold without boundary whose topological entropy is zero, while its action on second real homology has eigenvalue 2. Thus the topological entropy is strictly smaller than the logarithm of the homological spectral radius.

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