Smith–Thom inequality for real Deligne–Mumford stacks

Let X\mathcal{X} be a separated Deligne–Mumford stack of finite type over R\mathbb{R}, and let IXI_{\mathcal{X}} be the coarse moduli space of its inertia stack.

Real stack Smith–Thom conjecture. The dimension of the mod-22 cohomology of the real locus should satisfy

\textnormal{\dim} {\mathrm{H}}^\ast\left(\left|\mathcal{X}(\mathbb{R})\right|,\mathbb{Z}/2\right)\leq \textnormal{\dim} {\mathrm{H}}^\ast\left(I_{\mathcal{X}}(\mathbb{C}),\mathbb{Z}/2\right).

This is presented as the algebraic version obtained by restricting the topological groupoid conjecture to groupoids arising from real Deligne–Mumford stacks. Its status is not resolved in the supplied text.

Sources & referencesView supporting material

Primary source

Emiliano Ambrosi and Olivier de Gaay Fortman, “Topological groupoids with involution and real algebraic stacks”, arXiv:2504.02760 (2026).

Progress summary

Never refreshed

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

Solutions 0

No solutions have been posted yet.