# On almost k-covers of hypercubes

## TL;DR

This paper investigates the minimum number of affine hyperplanes needed to cover all vertices of a hypercube at least k times, extending known results and providing asymptotic solutions for large k.

## Contribution

It develops a fractional analogue of the problem, solves it asymptotically, and uses advanced algebraic tools to establish new bounds for specific cases.

## Key findings

- Fractional version of the problem is completely solved.
- Asymptotic analysis for fixed n and k→∞ is provided.
- Minimum hyperplanes needed for k=3 is at least n+3.

## Abstract

In this paper, we consider the following problem: what is the minimum number of affine hyperplanes in $\mathbb{R}^n$, such that all the vertices of $\{0, 1\}^n \setminus \{\vec{0}\}$ are covered at least $k$ times, and $\vec{0}$ is uncovered? The $k=1$ case is the well-known Alon-F\"uredi theorem which says a minimum of $n$ affine hyperplanes is required, proved by the Combinatorial Nullstellensatz. We develop an analogue of the Lubell-Yamamoto-Meshalkin inequality for subset sums, and completely solve the fractional version of this problem, which also provides an asymptotic answer to the integral version for fixed $n$ and $k \rightarrow \infty$. We also use a Punctured Combinatorial Nullstellensatz developed by Ball and Serra, to show that a minimum of $n+3$ affine hyperplanes is needed for $k=3$, and pose a conjecture for arbitrary $k$ and large $n$.