#####
Séminaire Lotharingien de Combinatoire, B28c (1992), 7
pp.

[Formerly: Publ. I.R.M.A. Strasbourg, 1992, 498/S-28, p.
45-51.]

# Andreas Dress and Christian Siebeneicher

# On the Integrality of the Witt Polynomials

**Abstract.**
Let rings denote the category of commutative rings with unity elements.
Many functors *F* from rings to rings have the following property:
char *A*=*p* implies that char *F*(*A*)=*p*.
We construct a functor *W*_{ G}: rings -> rings,
given a profinite group *G*. If *G* is
the cyclic group with *p* elements, then
*W*_{ C p} has the property that if
char *A*=*p*, then
char *W*_{ C p}(*A*) is different from *p*.
We provide several additional results on properties of this functor,
and study the functor for various groups *G*, in particular for
the profinite completion of the infinite cyclic group.

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