A comparison theorem for $f$-vectors of simplicial polytopes

dc.creatorBjörner, Anders
dc.date2006-05-12
dc.date2006-11-07
dc.date.accessioned2026-07-07T07:14:10Z
dc.date.available2026-07-07T07:14:10Z
dc.descriptionLet $f_i(P)$ denote the number of $i$-dimensional faces of a convex polytope $P$. Furthermore, let $S(n,d)$ and $C(n,d)$ denote, respectively, the stacked and the cyclic $d$-dimensional polytopes on $n$ vertices. Our main result is that for every simplicial $d$-polytope $P$, if $$ f_r(S(n_1,d))\le f_r(P) \le f_r(C(n_2,d)) $$ for some integers $n_1, n_2$ and $r$, then $$ f_s(S(n_1,d))\le f_s(P) \le f_s(C(n_2,d)) $$ for all $s$ such that $r<s$. For $r=0$ these inequalities are the well-known lower and upper bound theorems for simplicial polytopes. The result is implied by a certain ``comparison theorem'' for $f$-vectors, formulated in Section 4. Among its other consequences is a similar lower bound theorem for centrally-symmetric simplicial polytopes.
dc.description8 pages. Revised and corrected version. To appear in "Pure and Applied Mathematics Quarterly"
dc.identifierhttps://arxiv.org/abs/math/0605336
dc.identifierhttp://arxiv.org/abs/math/0605336
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/112766
dc.subjectCombinatorics
dc.subject05E99; 52B05
dc.titleA comparison theorem for $f$-vectors of simplicial polytopes
dc.typetext

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