  The Macaulay2 package Cremona performs some computations on rational and
birational maps between irreducible projective varieties. For instance, it
provides methods to compute degrees and projective degrees of rational maps
without any theoretical limitation, from which is derived a general method to
compute the push-forward to projective space of Segre classes. Moreover, the
computations can be done both deterministically and probabilistically. We give
here a brief description of the methods and algorithms implemented.
