Before revision:  This paper is intended as a survey and motivation for discussion, and does not claim to give definitive answers to the questions posed. We speculate that these questions are related, and that the nonlinear operators used in implicitly compositional language models may inform explicit compositional modelling .
After revision:  A third and newer question is whether a compositional model can be implemented on a quantum computer. Given the fundamentally linear nature of quantum mechanics, we propose that these questions are related, and that the nonlinear operators used in implicitly compositional language models may inform explicit compositional modelling .