The winding-number conjecture for dilated simplex Ehrhart h*-vectors

About 9 years old · traced to

Let Δrn={x∈[0,r]n:∑xi=r}\Delta_r^n=\{x\in[0,r]^n:\sum x_i=r\} be the (n−1)(n-1)-dimensional simplex, and call a decorated ordered set partition ((L1)l1,…,(Lk)lk)((L_1)_{l_1},\ldots,(L_k)_{l_k}) simplicial when 1≤li≤r−11\le l_i\le r-1 and ∑ili=r\sum_i l_i=r. For a simplicial ordered set partition with 1∈L11\in L_1, let wPw_P denote its winding number. Denote by m0,m1,…m_0,m_1,\ldots the numbers of such partitions having winding numbers wP=0,1,2,…w_P=0,1,2,\ldots. The dilated-simplex winding-number conjecture. The vector (m0,m1,…)(m_0,m_1,\ldots) equals the Ehrhart h∗h^*-vector of Δrn\Delta_r^n, and is obtained from the generating series

∑s=0∞(n−1+rsn−1)xs.\sum_{s=0}^{\infty}\binom{n-1+rs}{n-1}x^s.

The conjecture proposes a combinatorial interpretation of the Ehrhart h∗h^*-vector, extending the computationally observed winding-number enumeration for dilated simplices.

References

Primary source

Nick Early, “Conjectures for Ehrhart h^*-vectors of Hypersimplices and Dilated Simplices”, arXiv:1710.09507 (2017).

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.