We consider a continuous analogue of
[Babai et al. 1996]'s and
[Cai et al. 2000]'s problem of solving multiplicative
matrix equations. Given k+1 square matrices
A1, ..., Ak, C, all of the
same dimension, whose entries are real algebraic, we examine the
problem of deciding whether there exist non-negative reals
t1, ..., tk such that
We show that this problem is undecidable in general, but decidable under the assumption that the matrices A1, ..., Ak commute. Our results have applications to reachability problems for linear hybrid automata.
Our decidability proof relies on a number of theorems from algebraic and transcendental number theory, most notably those of Baker, Kronecker, Lindemann, and Masser, as well as some useful geometric and linear-algebraic results, including the Minkowski-Weyl theorem and a new (to the best of our knowledge) result about the uniqueness of strictly upper triangular matrix logarithms of upper unitriangular matrices. On the other hand, our undecidability result is shown by reduction from Hilbert's Tenth Problem.
Proceedings of LICS 16, 2016. 10 pages.
© 2016 IEEE Computer Society Press.