# evenCenter -- part of a CliffordModule

## Synopsis

• Usage:
c0 = M.evenCenter
• Outputs:
• c0, ,

## Description

Gives the action of Haag's center element y of the even Clifford algebra on the even part of M

 i1 : kk = ZZ/101 o1 = kk o1 : QuotientRing i2 : g = 1 o2 = 1 i3 : (S, qq, R, u, M1, M2, Mu1, Mu2)=randomNicePencil(kk,g); i4 : M = cliffordModule(M1,M2, R) o4 = CliffordModule{...6...} o4 : CliffordModule i5 : M.evenCenter o5 = {-4} | -49st+24t2 24s2t+13st2 -28st2 5s2t-5st2 -39t3 25st2-25t3 {-3} | 50s 49st+24t2 5st 9st 25t2 45t2 {-3} | -6t 6st+43t2 -49st-24t2 -50s2+15st 15t2 5st+49t2 {-3} | 6t -15t2 -24st 49st-24t2 -38t2 -15t2 {-3} | 9t -5st+5t2 0 0 49st-24t2 50s2-15st {-3} | -5t -28t2 0 0 24st -49st-24t2 {-3} | -3t -48st-26t2 28t2 -5st+5t2 -15t2 -6st-43t2 {-2} | 1 3t -5t -9t -6t -6t ------------------------------------------------------------------------ 0 0 | 0 0 | -45t2 25st2-25t3 | 25t2 39t3 | 9st -5s2t+5st2 | -5st -28st2 | 49st+24t2 -24s2t-13st2 | -50s -49st+24t2 | 8 8 o5 : Matrix R <--- R

## For the programmer

The object evenCenter is .