English

Unimodular rows over monoid extensions of overrings of polynomial rings

Commutative Algebra 2021-04-20 v1

Abstract

Let RR be a commutative Noetherian ring of dimension dd and MM a commutative cancellative torsion-free seminormal monoid. Then (1) Let AA be a ring of type R[d,m,n]R[d,m,n] and PP be a projective A[M]A[M]-module of rank rmax{2,d+1}r \geq max\{2,d+1\}. Then the action of E(A[M]P)E(A[M] \oplus P) on Um(A[M]P)Um(A[M] \oplus P) is transitive and (2) Assume (R,m,K)(R, m, K) is a regular local ring containing a field kk such that either charchar k=0k=0 or char char k=pk = p and trtr-degdeg K/Fp1K/\mathbb{F}_p \geq 1. Let AA be a ring of type R[d,m,n]R[d,m,n]^* and fRf\in R be a regular parameter. Then all finitely generated projective modules over A[M],A[M], A[M]fA[M]_f and A[M]RR(T)A[M] \otimes_R R(T) are free. When MM is free both results are due to Keshari and Lokhande.

Keywords

Cite

@article{arxiv.2104.09383,
  title  = {Unimodular rows over monoid extensions of overrings of polynomial rings},
  author = {Maria A. Mathew and Manoj K. Keshari},
  journal= {arXiv preprint arXiv:2104.09383},
  year   = {2021}
}

Comments

To appear in J. of Commutative Algebra