This book corresponds to a mathematical course given in 1986/87 at the University Louis Pasteur, Strasbourg.
This work is primarily intended for graduate students. The following
are necessary prerequisites : a few standard definitions in set theory, the
definition of rational integers, some elementary facts in Combinatorics
(maybe only Newton's binomial formula), some theorems of Analysis at
the level of high schools, and some elementary Algebra (basic results about
groups, rings, fields and linear algebra).