English

Witten's perturbation on strata with general adapted metrics

Differential Geometry 2018-01-12 v7 Algebraic Topology Geometric Topology

Abstract

Let MM be a stratum of a compact stratified space AA. It is equipped with a general adapted metric gg, which is slightly more general than the adapted metrics of Nagase and Brasselet-Hector-Saralegi. In particular, gg has a general type, which is an extension of the type of an adapted metric. A restriction on this general type is assumed, and then gg is called good. We consider the maximum/minimun ideal boundary condition, dmax/mind_{\text{\rm max/min}}, of the compactly supported de~Rham complex on MM, in the sense of Br\"uning-Lesch. Let Hmax/min(M)H^*_{\text{\rm max/min}}(M) and Δmax/min\Delta_{\text{\rm max/min}} denote the cohomology and Laplacian of dmax/mind_{\text{\rm max/min}}. The first main theorem states that Δmax/min\Delta_{\text{\rm max/min}} has a discrete spectrum satisfying a weak form of the Weyl's asymptotic formula. The second main theorem is a version of Morse inequalities using Hmax/min(M)H_{\text{\rm max/min}}^*(M) and what we call rel-Morse functions. An ingredient of the proofs of both theorems is a version for dmax/mind_{\text{\rm max/min}} of the Witten's perturbation of the de~Rham complex. Another ingredient is certain perturbation of the Dunkl harmonic oscillator previously studied by the authors using classical perturbation theory. Assume that AA is a stratified pseudomanifold, and consider its intersection homology IpˉH(A)I^{\bar p}H_*(A) with perversity pˉ\bar p; in particular, the lower and upper middle perversities are denoted by mˉ\bar m and nˉ\bar n, respectively. Then, for any perversity pˉmˉ\bar p\le\bar m, there is an associated good adapted metric on MM satisfying the Nagase isomorphism Hmaxr(M)IpˉHr(A)H^r_{\text{\rm max}}(M)\cong I^{\bar p}H_r(A)^* (rNr\in\N). If MM is oriented and pˉnˉ\bar p\ge\bar n, we also get Hminr(M)IpˉHr(A)H^r_{\text{\rm min}}(M)\cong I^{\bar p}H_r(A). Thus our version of the Morse inequalities can be described in terms of IpˉH(A)I^{\bar p}H_*(A).

Keywords

Cite

@article{arxiv.1507.07589,
  title  = {Witten's perturbation on strata with general adapted metrics},
  author = {Jesús A. Álvarez López and Manuel Calaza and Carlos Franco},
  journal= {arXiv preprint arXiv:1507.07589},
  year   = {2018}
}

Comments

46 pages. A few minor corrections were made