3 - Mathematics and its Applications
3 - Mathematics and its Applications
3 - Mathematics and its Applications
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56 Mitrofan M. Choban, Laurențiu I. CalmuțchiTheorem 5.6. Let f : X −→ X be a continuous mapping of a compactspace X into <strong>its</strong>elf. The following assertions are equivalent:1. If X 0 = X <strong>and</strong> X n+1 = f(X n ) for any n ∈ ω, then ∩{X n : n ∈ ω} isa singleton.2. For any positive number q < 1 there exists a family of pseudo-metricsD such that T = T (D) is the topology of the space X <strong>and</strong> d(f(x), f(y))