Many of the practical techniques developed for treating systems
described by periodic differential equations have arisen in different
fields of application; con- sequently some procedures have not always
been known to workers in areas that might benefit substantially from
them. Furthermore, recent analytical methods are computationally based
so that it now seems an opportune time for an applications-oriented book
to be made available that, in a sense, bridges the fields in which
equations with periodic coefficients arise and which draws together
analytical methods that are implemented readily. This book seeks to ftll
that role, from a user's and not a theoretician's view. The complexities
of periodic systems often demand a computational approach. Matrix
treatments therefore are emphasized here although algebraic methods have
been included where they are useful in their own right or where they
establish properties that can be exploited by the matrix approach. The
matrix development given calls upon the nomenclature and treatment of H.
D'Angelo, Linear Time- Varying Systems: Analysis and Synthesis (Boston:
Allyn and Bacon 1970) which deals with time-varying systems in general.
It is recommended for its modernity and comprehensive approach to
systems analysis by matrix methods. Since the present work is
applications-oriented no attempt has been made to be complete
theoretically by way of presenting all proofs, existence theorems and so
on. These can be found in D'Angelo and classic and well-developed
treatises such as McLachlan, N. W.: Theory and application of Mathieu
functions.