Corruption in a neoclassical growth model with a non-convex production function: comment

In Pereira and da Cruz Vieira (Int Rev Econ 57:335?C346, 2010), it is claimed that previous studies on corruption using the neoclassical growth model in the Ramsey tradition typically exploited a convex production function with productive government spending. Moreover, a non-convex intensive form technology representation is proposed as derived from the (presumptive) strictly convex function in levels. We show that none of these claims are true, for the general function is neither convex nor concave and fails to be linearly homogeneous. As a consequence, all the findings derived in Pereira and da Cruz Vieira (2010) are not peculiar to non-convex production functions.