Termwise equivalent asymptotic scales need not preserve expansions
= Termwise equivalent asymptotic scales need not preserve expansions
Even if $\phi_n\sim\psi_n$ for every $n$, an expansion in the scale $(\phi_n)$ need not induce one in $(\psi_n)$. A perturbation of $\psi_0$ that is smaller than $\phi_0$ but larger than $\phi_1$ supplies a counterexample.