定義
- A cover U of the bitopological space (X, τ1, τ2) is defined to be pairwise open if U ⊂τ_1∪τ_2 and U contains at least one non-empty member of τ1 and at least one non-empty member of τ2.
出典
- Encyclopedia of general topology.Edited by Klaas Pieter Hart, Jun-iti Nagata and Jerry E.Vaughan. Elsevier Science Publishers, B.V., Amsterdam, 2004.