role of semilcolon

[Reuben Sumner]

In the python interpreter doing 'a=1;b=2;b=3' does what I would
expect, three seperate assignments.  However ; doesn't seem to appear
in the language reference except in the list of delimeters.  Is the
above example formally valid python?

BTW as you can tell I am a newbie but I am impressed with the ease at
which I was able to implement some number theoretic algorithms
(gcd, primaility testing, pollard rho factoring, jacobian...)
Is there a big practical difference between using long numbers and
the mpz package?  (is the latter faster)

Reuben