Desingularization conjecture for orbifold Euler characteristics of quotients

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Let GG be a finite group, or more generally a linear algebraic group, acting on a variety XX, and let X→Y:=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 f∗Gf^G_*, the equivariant Chern class transformation C∗GC^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

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

Consequently,

f∗GC∗G(11X~/G,quo)=C∗G(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.

References

Primary source

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

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