Spectral gaps of simplicial complexes without large missing faces


Abstract in English

Let $X$ be a simplicial complex on $n$ vertices without missing faces of dimension larger than $d$. Let $L_{j}$ denote the $j$-Laplacian acting on real $j$-cochains of $X$ and let $mu_{j}(X)$ denote its minimal eigenvalue. We study the connection between the spectral gaps $mu_{k}(X)$ for $kgeq d$ and $mu_{d-1}(X)$. In particular, we establish the following vanishing result: If $mu_{d-1}(X)>(1-binom{k+1}{d}^{-1})n$, then $tilde{H}^{j}(X;mathbb{R})=0$ for all $d-1leq j leq k$. As an application we prove a fractional extension of a Hall-type theorem of Holmsen, Martinez-Sandoval and Montejano for general position sets in matroids.

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