arXiv Machine Learning

Representing Piecewise-Linear Functions by Functions with Minimal Arity

arXiv:2406. 02421v2 Announce Type: replace-cross Abstract: Any continuous piecewise-linear function $F\colon \mathbb{R}^{n}\to \mathbb{R}$ can be represented as a linear combination of $\max$ functions of at most $n+1$ affine-linear functions.

arXiv Machine Learning
Jul 27

Shallower ReLU Network Representations via Exact Linear Algebra

arXiv:2607. 21651v1 Announce Type: new Abstract: We prove that the maximum of $n$ real numbers is exactly representable by a ReLU network with two hidden layers for every $n\le 10$.

By Kilian Rue{\ss}, Gennadiy Averkov, Florestan Brunck, Moritz Grillo, Christoph Hertrich, Georg Loho, Jack Stade, Moritz Stargalla, Matthew Sun, Martin Winter
arXiv Machine Learning
Jun 5

Decomposition Polyhedra of Piecewise Linear Functions

arXiv:2410. 04907v2 Announce Type: replace-cross Abstract: In this paper we contribute to the frequently studied question of how to decompose a continuous piecewise linear (CPWL) function into a difference of two convex CPWL functions.

By Marie-Charlotte Brandenburg, Moritz Grillo, Christoph Hertrich
arXiv Machine Learning
Aug 19

Tight Bounds for Data-driven Multiple Hyper-parameter Tuning with Structured Loss Function

The paper establishes tight pseudo-dimension bounds for data-driven multiple hyper‑parameter tuning with structured loss functions. By refining upper bounds through real algebraic geometry and analyzing invariant connected sign cells, the authors avoid over‑counting and achieve sharper sample complexities. A multi‑regime lower‑bound framework demonstrates that these upper bounds are tight, and the approach is extended to general bi‑level validation‑loss tuning and broader semi‑algebraic applications.

By Anh Tuan Nguyen, Viet Anh Nguyen
arXiv Machine Learning
Jul 7

A simplex-based measure of symmetry

arXiv:2607. 03815v1 Announce Type: cross Abstract: For compact convex sets $L,K \subset \mathbb{R}^n$, denote by $\lambda_K(L)$ the smallest size of a homothet of $K$ that contains $L$.

By Egor Bakaev, Amir Yehudayoff
arXiv Machine Learning
Sep 4

Parameterized Hardness of Zonotope Containment and Neural Network Verification

The paper proves that several decision and approximation problems for ReLU neural networks are computationally hard. For any number of layers λ≥2, deciding whether a network’s output is positive (and thus whether it is surjective) is W[ℓ−1]-hard when parameterized by the input dimension d. In particular, for two-layer networks, the related geometric problem of zonotope non‑containment is W[1]-hard in the ambient dimension, and computing or approximating the Lp‑Lipschitz constant is NP‑hard and W[ℓ−1]-hard with respect to d. The results also show that these problems remain hard when parameterized by the number of layers for constant d, implying that naive enumeration algorithms running in n^{(ℓ−1)d}·poly(N) time are essentially optimal under the Exponential Time Hypothesis.

By Vincent Froese, Moritz Grillo, Christoph Hertrich, Moritz Stargalla