Maximum persistent Betti numbers of Čech complexes

This note proves that only a linear number of holes in a Cech complex of n points in R^d can persist over an interval of constant length. Specifically, for any fixed dimension p < d and fixed ε > 0, the number of p-dimensional holes in the ˇ Cech complex at radius 1 that persist to radius 1+ε is bounded above by a constant times n,where n is the number of points. The proof uses a packing argument supported by relating theCˇ ech complexes with corresponding snap complexes over the cells in a partition of space. The argument is self-contained and elementary, relying on geometric and combinatorial constructions rather than on the existing theory of sparse approximations or interleavings. The bound also applies to Alpha complexes and Vietoris–Rips complexes. While our result can be inferred from prior work on sparse filtrations, to our knowledge, no explicit statement or direct proof of this bound appears in the literature.