The Parameterized Complexity of Computing the VC-Dimension
Florent Foucaud, Harmender Gahlawat, Fionn Mc Inerney, Prafullkumar Tale
TL;DR
This work analyzes the computational complexity of VC-Dimension for set systems and graphs. It provides ETH-tight lower bounds for the naive brute-force approach and delivers a spectrum of parameterized results, including a $1$-additive approximation parameterized by the maximum degree $\Delta$ and a fixed-parameter algorithm by the dimension $D$, along with a fast $2^{\mathcal{O}({\rm tw}\cdot \log {\rm tw})}\cdot |V|$ algorithm for Gen-VC-Dimension on graphs of treewidth ${\rm tw}$. The results delineate tractable versus intractable parameter regimes and contrast the treewidth-based algorithm with existing double-exponential dependencies under ETH. They also establish strong lower bounds for related graph- and hypergraph-VC problems, guiding practical computation for graph-structured data and set systems. Overall, the paper significantly advances the understanding of VC-dimension computation from both algorithmic and complexity-theoretic viewpoints.
Abstract
The VC-dimension is a well-studied and fundamental complexity measure of a set system (or hypergraph) that is central to many areas of machine learning. We establish several new results on the complexity of computing the VC-dimension. In particular, given a hypergraph $\mathcal{H}=(\mathcal{V},\mathcal{E})$, we prove that the naive $2^{\mathcal{O}(|\mathcal{V}|)}$-time algorithm is asymptotically tight under the Exponential Time Hypothesis (ETH). We then prove that the problem admits a $1$-additive fixed-parameter approximation algorithm when parameterized by the maximum degree of $\mathcal{H}$ and a fixed-parameter algorithm when parameterized by its dimension, and that these are essentially the only such exploitable structural parameters. Lastly, we consider a generalization of the problem, formulated using graphs, which captures the VC-dimension of both set systems and graphs. We design a $2^{\mathcal{O}(\rm{tw}\cdot \log \rm{tw})}\cdot |V|$-time algorithm for any graph $G=(V,E)$ of treewidth $\rm{tw}$ (which, for a set system, applies to the treewidth of its incidence graph). This is in contrast with closely related problems that require a double-exponential dependency on the treewidth (assuming the ETH).
