Here's a first shot, 110 characters in body only -- lacks some error check (it's going to fail with anything less than two arguements), but if you consider the second arg to be 0, then that makes sense.. :-)

use strict;

my @poly1 = ( 2, 4, 6 );
my @poly2 = ( 3, 1, 0 );
my @poly4 = ( 5, 2, 1, 2 );

my @poly3 = p( \@poly1, \@poly2, \@poly4 );

print (join',',@poly3)."\n";

my @poly5 = p( \@poly4, \@poly1, \@poly2 );
print (join',',@poly5)."\n";

sub p {
  my$a=shift;my$b=shift;my(@c,$i,$j);for$i(0..$#$a){for$j(0..$#$b){$c[
+$i+$j]+=$$a[$i]*$$b[$j]}};@_?p(\@c,@_):\@c
}
[download]

Update: Cut down 5 more characters to 105, since you don't need to have $j around in the inner loop:

sub p {
  my$a=shift;my$b=shift;my(@c,$i);for$i(0..$#$a){for(0..$#$b){$c[$i+$_
+]+=$$a[$i]*$$b[$_]}};@_?p(\@c,@_):\@c
}
[download]

Update #2 as per tilly's reply, fixed the return problem to add that extra character.

---

Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain

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