Abstract
In 1971, McMullen and Walkup posed the following conjecture, which is called the generalized lower bound conjecture: If P is a simplicial d-polytope then its h-vector (h 0, h 1, …, h d ) satisfies \( {h_0}\leq {h_1}\leq \ldots \leq {h_{{\left\lfloor {{d \left/ {2} \right.}} \right\rfloor }}} \). Moreover, if h r−1 = h r for some \( r\leq \frac{1}{2}d \) then P can be triangulated without introducing simplices of dimension ≤d − r.
The first part of the conjecture was solved by Stanley in 1980 using the hard Lefschetz theorem for projective toric varieties. In this paper, we give a proof of the remaining part of the conjecture. In addition, we generalize this result to a certain class of simplicial spheres, namely those admitting the weak Lefschetz property.
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Murai, S., Nevo, E. On the generalized lower bound conjecture for polytopes and spheres. Acta Math 210, 185–202 (2013). https://doi.org/10.1007/s11511-013-0093-y
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DOI: https://doi.org/10.1007/s11511-013-0093-y