English

Homological congruence formulae for characteristic classes of singular varieties

Algebraic Geometry 2019-10-10 v2 Algebraic Topology

Abstract

For a pair (f,g)(f, g) of morphisms f:XZf:X \to Z and g:YZg:Y \to Z of (possibly singular) complex algebraic varieties X,Y,ZX,Y,Z, we present congruence formulae for the difference fTy(X)gTy(Y)f_*T_{y*}(X) -g_*T_{y*}(Y) of pushforwards of the corresponding motivic Hirzebruch classes TyT_{y*}. If we consider the special pair of a fiber bundle FEBF \hookrightarrow E \to B and the projection pr2:F×BBpr_2:F \times B \to B as such a pair (f,g)(f,g), then we get a congruence formula for the difference fTy(E)χy(F)Ty(B)f_*T_{y*}(E) -\chi_y(F)T_{y*}(B), which at degree level yields a congruence formula for χy(E)χy(F)χy(B)\chi_y(E) -\chi_y(F)\chi_y(B), expressed in terms of the Euler--Poincarv'e characteristic, Todd genus and signature in the case when F,E,BF, E, B are non-singular and compact. We also extend the finer congruence identities of Rovi--Yokura to the singular complex projective situation, by using the corresponding intersection (co)homology invariants.

Keywords

Cite

@article{arxiv.1802.00139,
  title  = {Homological congruence formulae for characteristic classes of singular varieties},
  author = {Laurentiu Maxim and Shoji Yokura},
  journal= {arXiv preprint arXiv:1802.00139},
  year   = {2019}
}

Comments

22 pages; comments are welcome, to appear in European Journal of Mathematics