The publisher apologises that upon publication an error was made in the equation listed for (4.3c) with + having been replaced in error with an x.
The correct equation is below:
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20220510174252940-0483:S0022112022003111:S0022112022003111_eqn1.png?pub-status=live)
Additionally a semi-colon was listed with in the second point within the conclusions section that was not required. The correct text is as below
(ii) optimally truncating the divergent expansion at
$N \sim 1/B$ and considering the exponentially small remainder
$\bar {q}$ by a solution of the form
$q=q_0+Bq_1+ \cdots$
$+ B^N q_N + \bar {q}$;