ABSTRACT
To motivate the form of the equations to be discussed in this section let us first reconsider equation (1.1) of chapter 7, () u ″ + u = ϵ f ( u , u ′ ; ϵ ) , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203745489/72d71235-428b-4675-8f02-a350ed612e08/content/eq1427.tif"/>
