  Consider $T(x)= d \, x$ (mod 1) acting on $S^1$, a Lipschitz potential $A:S^1
\to \mathbb{R}$, $0<\lambda<1$ and the unique function $b_\lambda:S^1 \to
\mathbb{R}$ satisfying $ b_\lambda(x) = \max_{T(y)=x} \{ \lambda \,
b_\lambda(y) + A(y)\}.$
  We will show that, when $\lambda \to 1$, the function $b_\lambda-
\frac{m(A)}{1-\lambda}$ converges uniformly to the calibrated subaction $V(x) =
\max_{\mu \in \mathcal{ M}} \int S(y,x) \, d \mu(y)$, where $S$ is the Ma\~ne
potential, $\mathcal{ M}$ is the set of invariant probabilities with support on
the Aubry set and $m(A)= \sup_{\mu \in \mathcal{M}} \int A\,d\mu$.
  For $\beta>0$ and $\lambda \in (0,1)$, there exists a unique fixed point
$u_{\lambda,\beta} :S^1\to \mathbb{R}$ for the equation
$e^{u_{\lambda,\beta}(x)} = \sum_{T(y)=x}e^{\beta A(y) +\lambda
u_{\lambda,\beta}(y)}$.
  It is known that as $\lambda \to 1$ the family $e^{[u_{\lambda,\beta}- \sup
u_{\lambda,\beta}]}$ converges uniformly to the main eigenfuntion $\phi_\beta $
for the Ruelle operator associated to $\beta A$.
  We consider $\lambda=\lambda(\beta)$, $\beta(1-\lambda(\beta))\to+\infty$ and
$\lambda(\beta) \to 1$, as $\beta \to\infty$. Under these hypothesis we will
show that $\frac{1}{\beta}(u_{\lambda,\beta}-\frac{P(\beta A)}{1-\lambda})$
converges uniformly to the above $V$, as $\beta\to \infty$.
  The parameter $\beta$ represents the inverse of temperature in Statistical
Mechanics and $\beta \to \infty$ means that we are considering that the
temperature goes to zero. Under these conditions we get selection of subaction
when $\beta \to \infty$.
