set a = the Element of NonZero R;
A1:
not the Element of NonZero R in {(0. R)}
by XBOOLE_0:def 5;
reconsider a = the Element of NonZero R as Element of R ;
set p = (0_ (n,R)) +* ((EmptyBag n),a);
reconsider p = (0_ (n,R)) +* ((EmptyBag n),a) as Function of (Bags n), the carrier of R ;
reconsider p = p as Function of (Bags n),R ;
reconsider p = p as Series of n,R ;
0_ (n,R) = (Bags n) --> (0. R)
by POLYNOM1:def 8;
then
dom (0_ (n,R)) = Bags n
;
then A5:
p . (EmptyBag n) = a
by FUNCT_7:31;
then
Support p = {(EmptyBag n)}
by A2, TARSKI:2;
then reconsider p = p as Polynomial of n,R by POLYNOM1:def 5;
take
p
; p is non-zero
a <> 0. R
by A1, TARSKI:def 1;
then
p <> 0_ (n,R)
by A5, POLYNOM1:22;
hence
p is non-zero
; verum