ABSTRACT
By suitably redefining variables it is always possible to bring a set of ordinary differential equations into a set of first-order differential equations of the type () https://www.w3.org/1998/Math/MathML"> d d t x = F ( x , t , μ ) . https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203750162/75f2bfa0-0ca3-4d38-8963-894d5bad8486/content/eq251.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/> The phase space spanned by the variables x is just a slight generalization of the concept of phase space used in elementary mechanics.
