The finiteness conjecture for $3 \times 3$ binary matrices
Journal:
arXiv
Published Date:
May 15, 2025
Abstract
The invariant polytope algorithm was a breakthrough in the joint spectral
radius computation, allowing to find the exact value of the joint spectral
radius for most matrix families~\cite{GP2013,GP2016}. This algorithm found many
applications in problems of functional analysis, approximation theory,
combinatorics, etc. In this paper we propose a modification of the invariant
polytope algorithm enlarging the class of problems to which it is applicable.
Precisely, we introduce mixed numeric and symbolic computations. A further
minor modification of augmenting the input set with additional matrices speeds
up the algorithm in certain cases. With this modifications we are able to
automatically prove the finiteness conjecture for all pairs of binary $3\times
3$ matrices and sign $2\times 2$ matrices.