MathOverflow is a question and answer site for professional mathematicians. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top


I have the following question: let $k$ a field with $char(k)= p>0$, which we can assume to be perfect, $W(k)$ the ring of Witt vector, and $a,b$ positive integers.

Consider the ring $R=W(k)[x,y]/(x^{p^a}-1,y^{p^b}-1)$ and let


Let $T=Spec(W(k)[t])$.

Is there a way to write $X$ as a stack quotient of $U=T\coprod T$ by multiplicative of additive finite group schemes (like product or extensions of $\mu_{p^{c_i}}$ and $\alpha_{p^{d_j}}$, for some bunch of integers $c_i,d_j$)?

share|cite|improve this question

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.