# Controllability of Kronecker Product Networks

## TL;DR

This paper establishes a comprehensive criterion for the controllability of Kronecker product networks, linking the controllability of individual factor networks to the composite network, with simplified conditions for diagonalizable factors and corrections to existing criteria.

## Contribution

It derives a necessary and sufficient controllability condition for Kronecker product networks with general directed graphs, including special cases and corrections to prior results.

## Key findings

- Derived a controllability condition for Kronecker networks
- Provided simplified conditions for diagonalizable factors
- Revised controllability criteria for multi-agent systems

## Abstract

A necessary and sufficient condition is derived for the controllability of Kronecker product networks, where the factor networks are general directed graphs. The condition explicitly illustrates how the controllability of the factor networks affects the controllability of the composite network. For the special case where at least one factor network is diagonalizable, an easily-verifiable condition is explicitly expressed. Furthermore, the controllability of higher-dimensional multi-agent systems is revisited, revealing that some controllability criterion reported in the literature does not hold. Consequently, a modified necessary and sufficient condition is established. The effectiveness of the new conditions is demonstrated through several examples.