This paper establishes a lower bound on the computational complexity o
f smooth functions between smooth manifolds. It generalizes one for fi
nite (Boolean) functions obtained (by Arbib and Spira [2]) by counting
variables. Instead of a counting procedure, which cannot be used in t
he infinite case, the dimension of the message space of a certain type
of revelation mechanism provides the bound. It also provides an intri
nsic measure of the number of variables on which the function depends.
This measure also gives a lower bound on computational costs associat
ed with realizing or implementing the function by a decentralized mech
anism, or by a game form.