Simplicial volume of open books in dimension 4
Thorben Kastenholz
TL;DR
This note proves that the simplicial volume of any 4-manifold admitting an open book decomposition vanishes, by adapting the Bucher-Neofytidis approach to the 4D setting and avoiding reliance on Geometrization. The method passes to irreducible pages via a JSJ-type decomposition, constructs arbitrarily small fundamental cycles on the pieces, and glues them along amenable boundary components to obtain a closed cycle with vanishing norm. A key consequence is that Quinn's asymmetric signature invariant cannot characterize open books in dimension four, even after connected-sum stabilizations. The results also imply the existence of 4-manifolds with vanishing asymmetric signature that do not admit open books, clarifying fundamental distinctions between 4D and higher-dimensional open book theory and expanding the class of 4-manifolds with vanishing simplicial volume in this context.
Abstract
In this short note we adapt a proof by Bucher and Neofytidis to prove that the simplicial volume of 4-manifolds admitting an open book decomposition vanishes. In particular this shows that Quinns signature invariant, which detects the existence of an open book decomposition in dimensions above 4, is insufficient to characterize open books in dimension 4, even if one allows arbitrary stabilizations via connected sums.
