Consider $A = \mathbb{R}[t_1,\ldots,t_{k}]$, the ring of real $k$-variate polynomials in the indeterminates $t_1,\ldots,t_k$. For $y\in\mathbb{R}$, define the element $p(y) \in A$ through $$ p(y) = t_1 y + t_2 y^2 + \cdots + t_k y^k \in A\,. $$

Let $I$ be the ideal in $A$ generated by $\{p(y)^2 \mid y \in \mathbb{R}\}$, and let $S = A/I$ be the quotient algebra of $A$ by $I$.

Has $S$ been studied? Does it have a name?

  • 1
    $\begingroup$ Your ring $S$ is a fairly simple ring (your description makes it look harder than it is). Is there something specific that you want to know about this ring? I do not know whether this particular ring has been studied exclusively in literature. $\endgroup$ – Mohan Aug 9 '18 at 18:14
  • $\begingroup$ @Mohan If you see a much simpler description of the ring, please feel free to add it to the question. The description I gave is the one that popped up in my application. I am interested in performing fast arithmetic in the ring, where "fast" means roughly in time $O(d\log^c d)$ for some $c$, where $d$ is the dimension of $S$ (which is easily determined). $\endgroup$ – Cornelius Brand Aug 10 '18 at 7:35
  • $\begingroup$ Let $u_m=\sum_{i+j=m} t_it_j$ for $2\leq m\leq 2k$. Then $I$ is generated by the $u_m$s. $\endgroup$ – Mohan Aug 10 '18 at 13:27
  • $\begingroup$ Thank you! I was aware of this (you get the dimension from that very quickly), but wasn't not sure if this was overall a more useful way to look at it. Is there any striking property of ideals of this form, or any well-known special class of rings that this falls into that comes to your mind? $\endgroup$ – Cornelius Brand Aug 11 '18 at 11:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.