witt(ZZ,ZZ,RingMap) -- The map induced on Witt rings by a RingMap.

Function: witt (missing documentation)
Usage:

witt(n, m, f)
Inputs:
- n, an integer,
- m, an integer,
- f, a ring map,
Outputs:
- Wf, an instance of the type WittRingMap,

Description

Given f: R -> S a RingMap between rings of positive characteristic and an integer $n \geq 1$, witt(n, f) returns the WittRingMap $W_n(f): W_n(R) \to W_n(S)$. If two integers $m \geq n \geq 1$ are passed, witt(n, m, f) returns the WittRingMap given by the composition $W_m(R) \to W_m(S) \to W_n(S)$, where the last map is truncation.

i1 : R = (ZZ/5)[x,y];

i2 : S = (ZZ/5)[a,b,c,d];

i3 : f = map(S, R, {a*b, c*d});

o3 : RingMap S <-- R

i4 : witt(2, 3, f)

o4 = WittRingMap Witt (S) <-- Witt (R)
                     2            3

o4 : WittRingMap

Ways to use this method:

witt(ZZ,ZZ,RingMap) -- The map induced on Witt rings by a RingMap.

The source of this document is in /build/reproducible-path/macaulay2-1.26.05+ds/M2/Macaulay2/packages/WittVectors/Documentation.m2:74:0.