“…Since R has a unique genus one Seifert surface, F and Σ are isotopic in the exterior of R. Then, by [30,Lemma 3.9], F and Σ cobound a product region P . At least one of the η i must lie in P because otherwise F would be isotopic to Σ in the exterior of the η i so F would be isotopic to F in the exterior of R , contradicting our assumption.…”