Cut-and-Paste on Foliated Bundles
英文摘要:
We discuss the behaviour of the signature index class of closed foliated bundles under the operation of cutting and pasting. Along the way we establish several index theoretic results: we define Atiyah-Patodi-Singer (APS) index classes for Dirac-type operators on foliated bundles with boundary; we prove a relative index theorem for the difference of two APS-index classes associated to different boundary conditions; we prove a gluing formula on closed foliated bundles that are the union of two foliated bundles with boundary; we establish a variational formula for APS-index classes of a 1-parameter family of Dirac-type operators on foliated bundles (this formula involves the noncommutative spectral flow of the boundary family). All these formulas take place in the $K$-theory of a suitable cross-product algebra. We then apply these results in order to find sufficient conditions ensuring the equality of the signature index classes of two cut-and-paste equivalent foliated bundles. We give applications to the question of when the Baum-Connes higher signatures of closed foliated bundles are cut-and-paste invariant.
机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。