Rota's unimodality conjecture for Whitney numbers of the second kind

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Let LL be a geometric lattice of rank rr. The Whitney numbers of the second kind are the integers Wi(L)W_i(L) for 0≤i≤r0\leq i\leq r. Rota's unimodality conjecture. For some 0≤k≤r0\leq k\leq r,

W0(L)≤⋯≤Wk−1(L)≤Wk(L)≥Wk+1(L)≥⋯≥Wr(L).W_0(L)\leq\dots\leq W_{k-1}(L)\leq W_k(L)\geq W_{k+1}(L)\geq\dots\geq W_r(L).

This is the companion unimodality conjecture for geometric lattices, raised alongside the first-kind version in the paper's discussion of future directions. The supplied text gives no evidence of a resolution.

References

Primary source

Matthew T. Stamps, “Topological representations of matroid maps”, arXiv:1104.4152 (2012).

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