“…At c = 0, F + = F − = (0, 0, 0), and the eigenvalues of the linearization of the origin are {0, ±i}. Thus, at c = 0, there is a 'Hopf-zero' bifurcation [1,12]. This is a generic codimension-1 bifurcation in the space of reversible volume-preserving systems; it is the bifurcation that we analyse in this paper.…”