Roman Pol's example of a Hurewicz set with one-dimensional square

Prelegent(ci)

Witold Marciszewski

Afiliacja

University of Warsaw

Język referatu

angielski

Termin

6 maja 2026 16:15

Pokój

p. 4050

Seminarium

Seminarium „Topologia i teoria mnogości”

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Paul Erdos gave an example of a closed one-dimensional subspace X of a Hilbert space whose square X x X is also one-dimensional. On the other hand, it is known that such example cannot be sigma- compact.
However, Roman Pol recently proved that, consistently, we can find a Hurewicz (a property slightly weaker than sigma-compactness) subset X of the Euclidean plane with one-dimensional square X x X.

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