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Examples related to Ulam’s fixed point problem. (English) Zbl 0787.54041

The paper deals with several examples related to the following problem posed by S. Ulam: given a continuum (connected compact metric space) \(M\), does there exist a constant \(\varepsilon > 0\) such that any \(\varepsilon\)-map \(f: M\to M\) (i.e. continuous map whose trajectories \(\{f^ n(x)\}^ \infty_{n=0}\), \(x\in M\), are bounded by \(\varepsilon\)), possess a fixed point? An example of a one-dimensional continuum such that for any \(\varepsilon\) there is a fixed point free \(\varepsilon\)-involution is given. Then it is shown that the Cartesian product of the circle and the Hilbert cube for any \(\varepsilon > 0\) admits a fixed point free \(\varepsilon\)-homeomorphism. At last an example of the rest point free dynamical system with trajectories uniformly bounded by arbitrary \(\varepsilon > 0\) defined on a three-dimensional manifold is provided.

MSC:

54H20 Topological dynamics (MSC2010)
37C10 Dynamics induced by flows and semiflows
54H25 Fixed-point and coincidence theorems (topological aspects)
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