Characteristic of Rings. Prime Fields

Simplicity of Rings of Differential Operators in Prime Characteristic

LetW be a finite dimensional representation of a linearly reductive group G over a field k. Motivated by their work on classical rings of invariants, Levasseur and Stafford asked whether the ring of invariants under G of the symmetric algebra of W has a simple ring of differential operators. In this paper, we show that this is true in prime characteristic. Indeed, if R is a graded subring of a ...

Coefficient Subrings of Certain Local Rings with Prime-power Characteristic

If R is a local ring whose radical J(R) is nilpotent and R/J(R) is a commutative field which is algebraic over GF(p), then R has at least one subring S such that S w*=,S,, where each S, is isomorphic to a Galois ring and S/J(S) is naturally isomorphic to R/J(R). Such subrings ofR are mutually isomorphic, but not necessarily conjugate in R.

Interpolation Series in Local Fields of Prime Characteristic

Diophantine Undecidability of Holomorphy Rings of Function Fields of Characteristic

Let K be a one-variable function field over a field of constants of characteristic 0. Let R be a holomorphy subring of K, not equal to K. We prove the following undecidability results for R: If K is recursive, then Hilbert’s Tenth Problem is undecidable in R. In general, there exist x1, . . . , xn ∈ R such that there is no algorithm to tell whether a polynomial equation with coefficients in Q(x...

Fixed-point-free Representations over Fields of Prime Characteristic

The irreducible representations over prime fields of characteristic p for those solvable groups which occur as groups of fixed-point-free automorphisms on finite groups are determined.