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Pairwise disjoint eight‐shaped curves in hybrid planes |
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| Authors: | Camillo Costantini |
| Institution: | Dipartimento di Matematica, Università di Torino, via Carlo Alberto 10, 10123 Torino, Italy |
| Abstract: | We introduce a suitable notion of eight‐shaped curve in the product S × ? of a Suslin line S for the real line ?, and we prove that if S is dense in itself, then every collection of pairwise disjoint eight‐shaped curves in S × ? is countable. This parallels a folklore result which holds for the real plane. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) |
| Keywords: | Eight‐shaped curve hybrid plane real plane Suslin line Suslin tree countable collection pairwise disjoint sets dense in itself totally ordered set separable space ccc space |