Generalized lower bound conjecture for complexes with bounded missing-face dimension

Let dotobreak0d ot obreak\geq 0 and 0<id+10<i\leq d+1 be integers. Let C(i,d)\mathcal{C}(i,d) be the family of dd-dimensional simplicial complexes with nonzero reduced dd-homology and no missing faces of dimension greater than ii. Write d+1=qi+rd+1=qi+r with q0q\geq 0 and 1ri1\leq r\leq i, and let S(i,d)S(i,d) be the join of qq copies of the boundary of the ii-simplex and the boundary of the rr-simplex. Let fj(Δ)\operatorname{f}_j(\Delta) denote the number of jj-dimensional faces of Δ\Delta. Generalized lower bound conjecture. For ΔC(i,d)\Delta\in\mathcal{C}(i,d),

fj(Δ)fj(S(i,d))\operatorname{f}_j(\Delta)\geq \operatorname{f}_j(S(i,d))

for every jj. Moreover, if equality is attained for every jj, then Δ=S(i,d)\Delta=S(i,d). The source presents this as a conjectural strengthening of known extremal results; the condition i(d+1)i\mid(d+1) is noted as an artifact of the proof in the surrounding theorem, so the full assertion remains open.

Sources & referencesView supporting material

Primary source

Eran Nevo, “Remarks on missing faces and generalized lower bounds on face numbers”, arXiv:0810.5487 (2009).

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.