Title: Refining the grading of irreducible Lie colour algebra representations

Abstract: We define the refining extension of representations for Lie colour algebras which simultaneously extends the representations and refines the grading to a larger grading group.We show that the refining extension provides a general method for deriving all finite-dimensional irreducible Lie colour algebra representations from those for Lie superalgebras. This method yields a bijection between equivalence classes but, despite this, Lie colour algebras maintain a non-trivial representation theory distinct from that of Lie superalgebras. We expect this result to be useful for the many applications of Lie colour algebras that make use of irreducible representations. In addition, we show that the refining extension provides a natural way to construct the Hilbert space realisation for colour algebra quantum-mechanical models by giving an example that has previously appeared in the literature.