The topology of a topological sum of orderable spaces is induced by the union of two order topologies

Authors

  • Nobuyuki Kemoto Oita University

Keywords:

orderable, suborderable, topological sum, ordered set

Abstract

It is known that the subspace $X=(0,1) \cup\{2\}$ in the real line $\mathbb{R}$ is the topological sum of the ordered subspaces $(0,1)$ and $\{2\}$ of $\mathbb{R}$ which is not orderable. In this paper, we prove that the topology of a topological sum of orderable spaces is induced by the union of two order topologies.

References

S. Eilenberg, Ordered topological spaces, Amer. J. Math., 63 (1941), 39-45.

R. Engelking, General Topology-Revised and completed ed., Heldermann Verlag, Berlin (1989).

G. Gruenhage, Generalized metric spaces, in Handbook of set-theoretic topology (ed. by K. Kunen & J. E. Vaughan), North-Holland Publishing Co., Amsterdam (1984), 423-501.

N. Kemoto, Orderability of spaces having ordered decompositions, Top. Proc., to appear.

P. R. Meyer, The Sorgenfrey topology is a join of orderable topologies, Czech. Math. J. 84 (1973), 402-403.

P. R. Meyer, V. Neumann-lara, R. G. Wilson, Is every GO-topology a join of two orderable topologies?, Proc. Amer. Math. Soc 84 (1982), no. 2, 291-296.

Published

2025-11-17

How to Cite

Kemoto, N. (2025). The topology of a topological sum of orderable spaces is induced by the union of two order topologies. Topology Proceedings, 68, 67–73. Retrieved from https://topology.journals.yorku.ca/index.php/tp/article/view/141

Issue

Section

General and Set Theoretic Topology (Research Papers)