  We consider an operation K \to L(K) on the set of simplicial complexes, which
we call the "doubling operation". This combinatorial operation has been
recently brought into toric topology by the work of Bahri, Bendersky, Cohen and
Gitler on generalised moment-angle complexes (also known as K-powers). The
crucial property of the doubling operation is that the moment-angle complex Z_K
can be identified with the real moment-angle complex RZ_L(K) for the double
L(K). As an application we prove the toral rank conjecture for Z_K by
estimating the lower bound of the cohomology rank (with rational coefficients)
of real moment-angle complexes RZ_K$. This paper extends the results of our
previous work, where the doubling operation for polytopes was used to prove the
toral rank conjecture for moment-angle manifolds.
