Arithmetic geometry and algebraic dynamical systems are flourishing
areas of mathematics. Both subjects have highly technical aspects, yet
both of- fer a rich supply of down-to-earth examples. Both have much to
gain from each other in techniques and, more importantly, as a means for
posing (and sometimes solving) outstanding problems. It is unlikely that
new graduate students will have the time or the energy to master both.
This book is in- tended as a starting point for either topic, but is in
content no more than an invitation. We hope to show that a rich common
vein of ideas permeates both areas, and hope that further exploration of
this commonality will result. Central to both topics is a notion of
complexity. In arithmetic geome- try 'height' measures arithmetical
complexity of points on varieties, while in dynamical systems 'entropy'
measures the orbit complexity of maps. The con- nections between these
two notions in explicit examples lie at the heart of the book. The
fundamental objects which appear in both settings are polynomi- als, so
we are concerned principally with heights of polynomials. By working
with polynomials rather than algebraic numbers we avoid local heights
and p-adic valuations.