ChainComplex Array -- degree shift

Synopsis

• Operator: SPACE

• Usage:

  D = C[i]

• Inputs:
  • C, a chain complex,
  • i, an array, an array [i] containing an integer i
• Outputs:
  • D, a chain complex, a new chain complex D in which D_j is C_(i+j). The signs of the differentials are reversed if i is odd.

Description

i1 : R = QQ[x..z];

i2 : C = res coker vars R

      1      3      3      1
o2 = R  <-- R  <-- R  <-- R  <-- 0
                                  
     0      1      2      3      4

o2 : ChainComplex

i3 : C[3]

      1      3      3      1
o3 = R  <-- R  <-- R  <-- R  <-- 0
                                  
     -3     -2     -1     0      1

o3 : ChainComplex