| Let Y be a compact, oriented 3-manifold with a contact form a. For any Dirac operator D , we study the asymptotic behavior of the spectral flow between D and D+cl&parl0;-ir2 a&parr0; as r → infinity. If a is the Thurston-Winkelnkemper contact form whose monodromy is the product of Dehn twists along disjoint circles, we prove that the next order term of the spectral flow function is O (r). |
