Veering triangulations admit strict angle structures

Abstract

Agol recently introduced the concept of a veering taut triangulation of a $3$–manifold, which is a taut ideal triangulation with some extra combinatorial structure. We define the weaker notion of a “veering triangulation” and use it to show that all veering triangulations admit strict angle structures. We also answer a question of Agol, giving an example of a veering taut triangulation that is not layered.