Sweeping the cd-index and the toric \(h\)-vector
The electronic journal of combinatorics, Tome 18 (2011) no. 1
We derive formulas for the ${\bf cd}$-index and the toric $h$-vector of a convex polytope $P$ from a sweeping by a hyperplane. These arise from interpreting the corresponding $S$-shelling of the dual of $P$. We describe a partition of the faces of the complete truncation of $P$ to reflect explicitly the nonnegativity of its ${\bf cd}$-index and what its components are counting. One corollary is a quick way to compute the toric $h$-vector directly from the ${\bf cd}$-index that turns out to be an immediate consequence of formulas of Bayer and Ehrenborg. We also propose an "extended toric" $h$-vector that fully captures the information in the flag $h$-vector.
DOI :
10.37236/553
Classification :
52B05
Mots-clés : cd-index, toric \(h\)-vector, convex polytope, flag \(h\)-vector
Mots-clés : cd-index, toric \(h\)-vector, convex polytope, flag \(h\)-vector
@article{10_37236_553,
author = {Carl W. Lee},
title = {Sweeping the cd-index and the toric \(h\)-vector},
journal = {The electronic journal of combinatorics},
year = {2011},
volume = {18},
number = {1},
doi = {10.37236/553},
zbl = {1216.52009},
url = {http://geodesic.mathdoc.fr/articles/10.37236/553/}
}
Carl W. Lee. Sweeping the cd-index and the toric \(h\)-vector. The electronic journal of combinatorics, Tome 18 (2011) no. 1. doi: 10.37236/553
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