I have a four part question involving the Novikov ring.
For part (1), I have:
$(\Sigma_{\gamma\in \tau}a_{\gamma}t^\gamma) +_{N} (\Sigma_{\gamma\in \tau}b_{\gamma}t^\gamma) =\Sigma_{\gamma\in \tau}(a_{\gamma}+b_{\gamma})t^\gamma$
We know that $(a_{\gamma}+b_{\gamma})\in \mathbb{Z}$ because $a_{\gamma} \in \mathbb{Z}$ and $b_{\gamma} \in \mathbb{Z}$
But I am unsure how to show that it satisfies the condition:
Similarly, I am unsure about how to prove closure for $\cdot_{N}$
For part (2), I just need to prove that it is an integral domain, so I must show that it is commutative, and I must show that it has no zero divisors. Again, I am unsure how to start the zero divisors portion of this part.
For part (3), I know the units in this ring must act as "multiplicative inverses", but I am unsure on how to express them.
For part (4), I must show that the Novikov ring can be generated by a single element. I am unsure how to approach this as well.
Any help would be appreciated.