The generalization of combination–
combination (C–C) synchronization of chaotic
n-dimensional (nD) fractional-order (0 < α ≤ 1)
dynamical systems is studied. Firstly, we replace arbitrary
four chaotic nD ordinary dynamical systems by
four chaotic nD fractional-order dynamical systems
which have unique solutions. Secondly, we extend the
scheme of a recent paper (Sun et al. in Nonlinear
Dyn 73: 1211–1222, 2013) to study the generalization
of C–C synchronization among four nDfractionalorder
dynamical systems. Examples of combination–
combination synchronization among four identical or
different of 6D chaotic fractional-order systems are discussed.
The analytical formula of the control functions
is tested numerically to achieve C–C synchronization,
and good agreement is found