Videos

Recent results on the grading of local cohomology modules

Presenter
May 6, 2013
Keywords:
  • characteristic p
  • commutative algebra
  • birational algebraic geometry
  • multiplier ideals
  • singularities of varieties
  • local cohomology
  • graded commutative algebra
MSC:
  • 13A35
  • 13A15
  • 13A18
  • 13Axx
  • 13-xx
  • 14-xx
  • 14Exx
  • 14E05
  • 14E15
Abstract
After a brief introduction to local cohomology I am going to discuss the result of my student Yi Zhang on the grading of local cohomology modules in characteristic p>0 and its recent extension to characteristic 0 by Linquan Ma and Wenliang Zhang. Namely, if R is a polynomial ring in n variables over a field and m \subset R is the maximal ideal generated by the variables then it is well-known that H^n_m(R) with its natural grading is isomorphic to E(n), i.e. the naturally graded injective hull E of R/m degree-shifted downward by n. It has also been well-known that if I \subset R is any ideal, then the local cohomology module H^i_m(H^j_I(R)) is isomorphic to a direct sum of a finite number of copies of E. Yi, Linquan and Wenliang sharpened this result by showing that if I \subset R is any homogeneous ideal, then the local cohomology module H^i_m(H^j_I(R)), with its natural grading is isomorphic to a direct sum of a finite number of copies of E(n). Some other related recent results will also be discussed.
Supplementary Materials