Desingularization conjecture for orbifold Euler characteristics of quotients

From papers

Let GG be a finite group, or more generally a linear algebraic group, acting on a variety XX, and let XY:=X/GX\to Y:=X/G be the quotient. A GG-variety is a variety with a GG-action, and a proper GG-morphism is a proper morphism compatible with the GG-actions. Let X~\tilde{X} be a GG-variety and let f:X~Xf:\tilde{X}\to X be a proper GG-morphism. The conjecture concerns the equivariant pushforward fGf^G_*, the equivariant Chern class transformation CGC^G_*, and the constructible functions 11X~/G,quo1\hskip-3.5pt1_{\tilde{X}/G, quo} and 11X/G,orb1\hskip-3.5pt1_{X/G, orb} associated with the quotient and orbifold theories. Desingularization conjecture for orbifold Euler characteristics. There exists such a GG-variety X~\tilde{X} and proper GG-morphism ff satisfying

fG(11X~/G,quo)=11X/G,orb.f^G_*(1\hskip-3.5pt1_{\tilde{X}/G, quo})=1\hskip-3.5pt1_{X/G, orb}.

Consequently,

fGCG(11X~/G,quo)=CG(11X/G,orb),f^G_*C^G_*(1\hskip-3.5pt1_{\tilde{X}/G, quo})=C^G_*(1\hskip-3.5pt1_{X/G, orb}),

and the zeroth degrees satisfy

χ(X~/G)=χ(X;G).\chi(\tilde{X}/G)=\chi(X;G).

The conjecture proposes that the orbifold invariants of a quotient can be realized through a suitable equivariant desingularization. The source gives no resolution status or further conditions on the construction of X~\tilde{X} and ff, so the claim is recorded as open.

Progress summary

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Sources & referencesView supporting material

Primary source

Toru Ohmoto, “Equivariant Chern classes of singular algebraic varieties with group actions”, arXiv:math/0407348 (2004).

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