  In this work I present a generalization of Amdahl's law on the limits of a
parallel implementation with many processors. In particular I establish some
mathematical relations involving the number of processors and the dimension of
the treated problem, and with these conditions I define, on the ground of the
reachable speedup, some classes of parallelism for the implementations. I also
derive a condition for obtaining superlinear speedup. The used mathematical
technics are those of differential calculus. I describe some examples from
classical problems offered by the specialized literature on the subject.
